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Rafiei N, Mitchell CS, Tedesco CR, Chen J, Choi EA, Roughley S, Jean-Richard-Dit-Bressel P, Kumar NN, McNally GP, Herzog H, Begg DP. Chemogenetic activation of arcuate nucleus NPY and NPY/AgRP neurons increases feeding behaviour in mice. Neuropeptides 2024; 107:102454. [PMID: 38970907 DOI: 10.1016/j.npep.2024.102454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 07/01/2024] [Accepted: 07/02/2024] [Indexed: 07/08/2024]
Abstract
Neuropeptide Y (NPY) plays a crucial role in controlling energy homeostasis and feeding behaviour. The role of NPY neurons located in the arcuate nucleus of the hypothalamus (Arc) in responding to homeostatic signals has been the focus of much investigation, but most studies have used AgRP promoter-driven models, which do not fully encompass Arc NPY neurons. To directly investigate NPY-expressing versus AgRP-expressing Arc neurons function, we utilised chemogenetic techniques in NPY-Cre and AgRP-Cre animals to activate Arc NPY or AgRP neurons in the presence of food and food-related stimuli. Our findings suggest that chemogenetic activation of the broader population of Arc NPY neurons, including AgRP-positive and AgRP-negative NPY neurons, has equivalent effects on feeding behaviour as activation of Arc AgRP neurons. Our results demonstrate that these Arc NPY neurons respond specifically to caloric signals and do not respond to non-caloric signals, in line with what has been observed in AgRP neurons. Activating Arc NPY neurons significantly increases food consumption and influences macronutrient selection to prefer fat intake.
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Affiliation(s)
- Neda Rafiei
- School of Psychology, University of New South Wales, Australia; School of Pharmacy, University of Sydney, Australia.
| | - Caitlin S Mitchell
- School of Psychology, University of New South Wales, Australia; School of Biomedical Sciences and Pharmacy, University of Newcastle, Australia
| | | | - Jessica Chen
- School of Psychology, University of New South Wales, Australia
| | - Eun A Choi
- School of Psychology, University of New South Wales, Australia
| | | | | | - Natasha N Kumar
- School of Biomedical Sciences, University of New South Wales, Australia
| | - Gavan P McNally
- School of Psychology, University of New South Wales, Australia
| | | | - Denovan P Begg
- School of Psychology, University of New South Wales, Australia
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2
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Sutton Hickey AK, Becker J, Karolczak EO, Lutas A, Krashes MJ. Dietary fat content and absorption shape standard diet devaluation through hunger circuits. Mol Metab 2024; 89:102021. [PMID: 39216534 DOI: 10.1016/j.molmet.2024.102021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2024] [Revised: 08/27/2024] [Accepted: 08/27/2024] [Indexed: 09/04/2024] Open
Abstract
OBJECTIVE Exposure to 60% high fat diet (HFD) leads to a robust consummatory preference over well-balanced chow standard diet (SD) when mice are presented with a choice. This passive HFD-induced SD devaluation following HFD challenge and withdrawal is highlighted by the significant reduction in SD food intake even in states of caloric deprivation. The elements of HFD that lead to this SD depreciation remains unclear. Possibly important factors include the amount and type of fat contained in a diet as well as past eating experiences dependent on sensory properties including taste and post ingestive feedback. We aimed to explore the role of these components to HFD-induced SD devaluation. METHODS Wildtype mice were longitudinally presented discrete HFDs in conjunction with SD and feeding and metabolic parameters were analyzed. A separate cohort of animals were assessed for acute HFD preference in 3 conditions: 1) ad libitum fed (sated), 2) overnight fasted (physiologically hungry), and 3) ad libitum fed (artificially hungry), elicited through chemogenetic Agouti-related peptide (AgRP) neuron activation. Population dynamics of AgRP neurons were recorded to distinct inaccessible and accessible diets both before and after consummatory experience. Transient receptor potential channel type M5 (TRPM5) knockout mice were used to investigate the role of fat taste perception and preference to HFD-induced SD devaluation. The clinically approved lipase inhibitor orlistat was used to test the contribution of fat absorption to HFD-induced SD devaluation. RESULTS HFD-induced SD devaluation is dependent on fat content, composition, and preference. This effect scaled both in strength and latency with higher percentages of animal fat. 60% HFD was preferred and almost exclusively consumed in preference to other diets across hours and days, but this was not as evident upon initial introduction over seconds and minutes, suggesting ingestive experience is critical. Optical fiber photometry recordings of AgRP activity supported this notion as neuronal suppression by the different diets was contingent on prior intake. While taste transduced via TRPM5 influenced HFD-evoked weight gain, it failed to impact either HFD preference or HFD-induced SD devaluation. Perturbation of post ingestive feedback through orlistat-mediated diminishment of fat absorption prevented HFD-evoked weight gain and abolished HFD-induced SD devaluation. CONCLUSIONS Post ingestive feedback via fat digestion is vital for expression of HFD-induced SD devaluation.
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Affiliation(s)
- Ames K Sutton Hickey
- Department of Psychology and Neuroscience, Temple University, Philadelphia, PA, USA
| | - Jordan Becker
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA; NIH-Brown University Graduate Program in Neuroscience, Bethesda, MD, USA
| | - Eva O Karolczak
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Andrew Lutas
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Michael J Krashes
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA.
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3
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Yagoub S, Chesters RA, Ott J, Zhu J, Cantacorps L, Ritter K, Lippert RN. Acute elevated dietary fat alone is not sufficient to decrease AgRP projections in the paraventricular nucleus of the hypothalamus in mice. Sci Rep 2024; 14:20043. [PMID: 39209992 PMCID: PMC11362280 DOI: 10.1038/s41598-024-70870-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Accepted: 08/22/2024] [Indexed: 09/04/2024] Open
Abstract
Within the brain, the connections between neurons are constantly changing in response to environmental stimuli. A prime environmental regulator of neuronal activity is diet, and previous work has highlighted changes in hypothalamic connections in response to diets high in dietary fat and elevated sucrose. We sought to determine if the change in hypothalamic neuronal connections was driven primarily by an elevation in dietary fat alone. Analysis was performed in both male and female animals. We measured Agouti-related peptide (AgRP) neuropeptide and Synaptophysin markers in the paraventricular nucleus of the hypothalamus (PVH) in response to an acute 48 h high fat diet challenge. Using two image analysis methods described in previous studies, an effect of a high fat diet on AgRP neuronal projections in the PVH of male or female mice was not identified. These results suggest that it may not be dietary fat alone that is responsible for the previously published alterations in hypothalamic connections. Future work should focus on deciphering the role of individual macronutrients on neuroanatomical and functional changes.
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Affiliation(s)
- Selma Yagoub
- German Institute for Human Nutrition Potsdam-Rehbrücke, Nuthetal, Germany
- University of Potsdam, Potsdam, Germany
| | - Robert A Chesters
- German Institute for Human Nutrition Potsdam-Rehbrücke, Nuthetal, Germany
- NeuroCure Cluster of Excellence, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Jonathan Ott
- German Institute for Human Nutrition Potsdam-Rehbrücke, Nuthetal, Germany
- University of Potsdam, Potsdam, Germany
| | - Jiajie Zhu
- German Institute for Human Nutrition Potsdam-Rehbrücke, Nuthetal, Germany
- University of Potsdam, Potsdam, Germany
- NeuroCure Cluster of Excellence, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Lídia Cantacorps
- German Institute for Human Nutrition Potsdam-Rehbrücke, Nuthetal, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Katrin Ritter
- German Institute for Human Nutrition Potsdam-Rehbrücke, Nuthetal, Germany
| | - Rachel N Lippert
- German Institute for Human Nutrition Potsdam-Rehbrücke, Nuthetal, Germany.
- German Center for Diabetes Research (DZD), Neuherberg, Germany.
- NeuroCure Cluster of Excellence, Charité - Universitätsmedizin Berlin, Berlin, Germany.
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4
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Aitken TJ, Liu Z, Ly T, Shehata S, Sivakumar N, La Santa Medina N, Gray LA, Zhang J, Dundar N, Barnes C, Knight ZA. Negative feedback control of hypothalamic feeding circuits by the taste of food. Neuron 2024:S0896-6273(24)00539-7. [PMID: 39153476 DOI: 10.1016/j.neuron.2024.07.017] [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: 06/20/2023] [Revised: 06/12/2024] [Accepted: 07/22/2024] [Indexed: 08/19/2024]
Abstract
The rewarding taste of food is critical for motivating animals to eat, but whether taste has a parallel function in promoting meal termination is not well understood. Here, we show that hunger-promoting agouti-related peptide (AgRP) neurons are rapidly inhibited during each bout of ingestion by a signal linked to the taste of food. Blocking these transient dips in activity via closed-loop optogenetic stimulation increases food intake by selectively delaying the onset of satiety. We show that upstream leptin-receptor-expressing neurons in the dorsomedial hypothalamus (DMHLepR) are tuned to respond to sweet or fatty tastes and exhibit time-locked activation during feeding that is the mirror image of downstream AgRP cells. These findings reveal an unexpected role for taste in the negative feedback control of ingestion. They also reveal a mechanism by which AgRP neurons, which are the primary cells that drive hunger, are able to influence the moment-by-moment dynamics of food consumption.
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Affiliation(s)
- Tara J Aitken
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Zhengya Liu
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Truong Ly
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Sarah Shehata
- Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Nilla Sivakumar
- Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Naymalis La Santa Medina
- Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Lindsay A Gray
- Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Jingkun Zhang
- Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Naz Dundar
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Chris Barnes
- Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Zachary A Knight
- Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA; Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA; Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA.
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5
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Catalbas K, Pattnaik T, Congdon S, Nelson C, Villano LC, Sweeney P. Hypothalamic AgRP neurons regulate the hyperphagia of lactation. Mol Metab 2024; 86:101975. [PMID: 38925247 PMCID: PMC11268337 DOI: 10.1016/j.molmet.2024.101975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 06/19/2024] [Accepted: 06/21/2024] [Indexed: 06/28/2024] Open
Abstract
OBJECTIVE The lactational period is associated with profound hyperphagia to accommodate the energy demands of nursing. These changes are important for the long-term metabolic health of the mother and children as altered feeding during lactation increases the risk of mothers and offspring developing metabolic disorders later in life. However, the specific behavioral mechanisms and neural circuitry mediating the hyperphagia of lactation are incompletely understood. METHODS Here, we utilized home cage feeding devices to characterize the dynamics of feeding behavior in lactating mice. A combination of pharmacological and behavioral assays were utilized to determine how lactation alters meal structure, circadian aspects of feeding, hedonic feeding, and sensitivity to hunger and satiety signals in lactating mice. Finally, we utilized chemogenetic, immunohistochemical, and in vivo imaging approaches to characterize the role of hypothalamic agouti-related peptide (AgRP) neurons in lactational-hyperphagia. RESULTS The lactational period is associated with increased meal size, altered circadian patterns of feeding, reduced sensitivity to gut-brain satiety signals, and enhanced sensitivity to negative energy balance. Hypothalamic AgRP neurons display increased sensitivity to negative energy balance and altered in vivo activity during the lactational state. Further, using in vivo imaging approaches we demonstrate that AgRP neurons are directly activated by lactation. Chemogenetic inhibition of AgRP neurons acutely reduces feeding in lactating mice, demonstrating an important role for these neurons in lactational-hyperphagia. CONCLUSIONS Together, these results show that lactation collectively alters multiple components of feeding behavior and position AgRP neurons as an important cellular substrate mediating the hyperphagia of lactation.
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Affiliation(s)
- Kerem Catalbas
- University of Illinois Urbana-Champaign, Department of Molecular and Integrative Physiology, USA; University of Illinois Urbana-Champaign Neuroscience Program, USA
| | - Tanya Pattnaik
- University of Illinois Urbana-Champaign, Department of Molecular and Integrative Physiology, USA
| | - Samuel Congdon
- University of Illinois Urbana-Champaign, Department of Molecular and Integrative Physiology, USA
| | - Christina Nelson
- University of Illinois Urbana-Champaign, Department of Molecular and Integrative Physiology, USA
| | - Lara C Villano
- University of Illinois Urbana-Champaign, Department of Molecular and Integrative Physiology, USA
| | - Patrick Sweeney
- University of Illinois Urbana-Champaign, Department of Molecular and Integrative Physiology, USA; University of Illinois Urbana-Champaign Neuroscience Program, USA.
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6
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Ferrario CR, Münzberg-Gruening H, Rinaman L, Betley JN, Borgland SL, Dus M, Fadool DA, Medler KF, Morton GJ, Sandoval DA, de La Serre CB, Stanley SA, Townsend KL, Watts AG, Maruvada P, Cummings D, Cooke BM. Obesity- and diet-induced plasticity in systems that control eating and energy balance. Obesity (Silver Spring) 2024; 32:1425-1440. [PMID: 39010249 PMCID: PMC11269035 DOI: 10.1002/oby.24060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 04/16/2024] [Accepted: 04/17/2024] [Indexed: 07/17/2024]
Abstract
In April 2023, the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), in partnership with the National Institute of Child Health and Human Development, the National Institute on Aging, and the Office of Behavioral and Social Sciences Research, hosted a 2-day online workshop to discuss neural plasticity in energy homeostasis and obesity. The goal was to provide a broad view of current knowledge while identifying research questions and challenges regarding neural systems that control food intake and energy balance. This review includes highlights from the meeting and is intended both to introduce unfamiliar audiences with concepts central to energy homeostasis, feeding, and obesity and to highlight up-and-coming research in these areas that may be of special interest to those with a background in these fields. The overarching theme of this review addresses plasticity within the central and peripheral nervous systems that regulates and influences eating, emphasizing distinctions between healthy and disease states. This is by no means a comprehensive review because this is a broad and rapidly developing area. However, we have pointed out relevant reviews and primary articles throughout, as well as gaps in current understanding and opportunities for developments in the field.
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Grants
- P30 DK048520 NIDDK NIH HHS
- NSF1949989 National Science Foundation
- T32 DC000044 NIDCD NIH HHS
- R01 DK133464 NIDDK NIH HHS
- R01 DK089056 NIDDK NIH HHS
- R01 DK130246 NIDDK NIH HHS
- R01 DK124801 NIDDK NIH HHS
- R01 DK100685 NIDDK NIH HHS
- R01 DK124238 NIDDK NIH HHS
- R01 DK130875 NIDDK NIH HHS
- R01 DK125890 NIDDK NIH HHS
- Z99 DK999999 Intramural NIH HHS
- R01 DK124461 NIDDK NIH HHS
- K26 DK138368 NIDDK NIH HHS
- R01 DK121995 NIDDK NIH HHS
- R01 DK121531 NIDDK NIH HHS
- P30 DK089503 NIDDK NIH HHS
- P01 DK119130 NIDDK NIH HHS
- R01 DK118910 NIDDK NIH HHS
- R01 AT011683 NCCIH NIH HHS
- Reported research was supported by DK130246, DK092587, AT011683, MH059911, DK100685, DK119130, DK124801, DK133399, AG079877, DK133464, T32DC000044, F31DC016817, NSF1949989, DK089056, DK124238, DK138368, DK121995, DK125890, DK118910, DK121531, DK124461, DK130875; Canada Research Chair: 950-232211, CIHRFDN148473, CIHRPJT185886; USDA Predoctoral Fellowship; Endowment from the Robinson Family and Tallahassee Memorial Hospital; Department of Defense W81XWH-20-1-0345 and HT9425-23-1-0244; American Diabetes Association #1-17-ACE-31; W.M. Keck Foundation Award; National Science Foundation CAREER 1941822
- R01 DK133399 NIDDK NIH HHS
- HT9425-23-1-0244 Department of Defense
- R01 DK092587 NIDDK NIH HHS
- W81XWH-20-1-0345 Department of Defense
- 1941822 National Science Foundation
- R01 MH059911 NIMH NIH HHS
- F31 DC016817 NIDCD NIH HHS
- R01 AG079877 NIA NIH HHS
- P30 DK017047 NIDDK NIH HHS
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Affiliation(s)
- Carrie R Ferrario
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan, USA
| | - Heike Münzberg-Gruening
- Laboratory of Central Leptin Signaling, Pennington Biomedical Research Center, Baton Rouge, Louisiana, USA
| | - Linda Rinaman
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, Florida, USA
| | - J Nicholas Betley
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Stephanie L Borgland
- Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
| | - Monica Dus
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Debra A Fadool
- Department of Biological Science, Program in Neuroscience, Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida, USA
| | - Kathryn F Medler
- School of Animal Sciences, Virginia Tech, Blacksburg, Virginia, USA
| | - Gregory J Morton
- Department of Medicine, University of Washington Medicine Diabetes Institute at South Lake Union, Seattle, Washington, USA
| | - Darleen A Sandoval
- Department of Pediatrics, Section of Nutrition, University of Colorado-Anschutz Medical Campus, Aurora, Colorado, USA
| | - Claire B de La Serre
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Sarah A Stanley
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Kristy L Townsend
- Department of Neurological Surgery, The Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Alan G Watts
- Department of Biological Sciences, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, California, USA
| | - Padma Maruvada
- National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, USA
| | - Diana Cummings
- National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, USA
| | - Bradley M Cooke
- National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, USA
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Deehan EC, Mocanu V, Madsen KL. Effects of dietary fibre on metabolic health and obesity. Nat Rev Gastroenterol Hepatol 2024; 21:301-318. [PMID: 38326443 DOI: 10.1038/s41575-023-00891-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/18/2023] [Indexed: 02/09/2024]
Abstract
Obesity and metabolic syndrome represent a growing epidemic worldwide. Body weight is regulated through complex interactions between hormonal, neural and metabolic pathways and is influenced by numerous environmental factors. Imbalances between energy intake and expenditure can occur due to several factors, including alterations in eating behaviours, abnormal satiation and satiety, and low energy expenditure. The gut microbiota profoundly affects all aspects of energy homeostasis through diverse mechanisms involving effects on mucosal and systemic immune, hormonal and neural systems. The benefits of dietary fibre on metabolism and obesity have been demonstrated through mechanistic studies and clinical trials, but many questions remain as to how different fibres are best utilized in managing obesity. In this Review, we discuss the physiochemical properties of different fibres, current findings on how fibre and the gut microbiota interact to regulate body weight homeostasis, and knowledge gaps related to using dietary fibres as a complementary strategy. Precision medicine approaches that utilize baseline microbiota and clinical characteristics to predict individual responses to fibre supplementation represent a new paradigm with great potential to enhance weight management efficacy, but many challenges remain before these approaches can be fully implemented.
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Affiliation(s)
- Edward C Deehan
- Department of Food Science and Technology, University of Nebraska, Lincoln, NE, USA
- Nebraska Food for Health Center, Lincoln, NE, USA
| | - Valentin Mocanu
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Karen L Madsen
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.
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8
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Reichenbach A, Dempsey H, Andrews ZB. Metabolic sensing in AgRP regulates sucrose preference and dopamine release in the nucleus accumbens. J Neuroendocrinol 2024; 36:e13389. [PMID: 38599683 DOI: 10.1111/jne.13389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 03/18/2024] [Accepted: 03/26/2024] [Indexed: 04/12/2024]
Abstract
Hunger increases the motivation for calorie consumption, often at the expense of low-taste appeal. However, the neural mechanisms integrating calorie-sensing with increased motivation for calorie consumption remain unknown. Agouti-related peptide (AgRP) neurons in the arcuate nucleus of the hypothalamus sense hunger, and the ingestion of caloric solutions promotes dopamine release in the absence of sweet taste perception. Therefore, we hypothesised that metabolic-sensing of hunger by AgRP neurons would be essential to promote dopamine release in the nucleus accumbens in response to caloric, but not non-caloric solutions. Moreover, we examined whether metabolic sensing in AgRP neurons affected taste preference for bitter solutions under conditions of energy need. Here we show that impaired metabolic sensing in AgRP neurons attenuated nucleus accumbens dopamine release in response to sucrose, but not saccharin, consumption. Furthermore, metabolic sensing in AgRP neurons was essential to distinguish nucleus accumbens dopamine response to sucrose consumption when compared with saccharin. Under conditions of hunger, metabolic sensing in AgRP neurons increased the preference for sucrose solutions laced with the bitter tastant, quinine, to ensure calorie consumption, whereas mice with impaired metabolic sensing in AgRP neurons maintained a strong aversion to sucrose/quinine solutions despite ongoing hunger. In conclusion, we demonstrate normal metabolic sensing in AgRP neurons drives the preference for calorie consumption, primarily when needed, by engaging dopamine release in the nucleus accumbens.
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Affiliation(s)
- Alex Reichenbach
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Harry Dempsey
- Florey Institute of Neuroscience & Mental Health, Parkville, Victoria, Australia
| | - Zane B Andrews
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
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9
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McMorrow HE, Lorch CM, Hayes NW, Fleps SW, Frydman JA, Xia JL, Samms RJ, Beutler LR. Incretin hormones and pharmacomimetics rapidly inhibit AgRP neuron activity to suppress appetite. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.18.585583. [PMID: 38562891 PMCID: PMC10983981 DOI: 10.1101/2024.03.18.585583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Analogs of the incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP) have become mainstays of obesity and diabetes management. However, both the physiologic role of incretin hormones in the control of appetite and the pharmacologic mechanisms by which incretin-mimetic drugs suppress caloric intake remain incompletely understood. Hunger-promoting AgRP-expressing neurons are an important hypothalamic population that regulates food intake. Therefore, we set out to determine how incretins analogs affect their activity in vivo. Using fiber photometry, we observed that both GIP receptor (GIPR) and GLP-1 receptor (GLP-1R) agonism acutely inhibit AgRP neuron activity in fasted mice and reduce the response of AgRP neurons to food. Moreover, optogenetic stimulation of AgRP neurons partially attenuated incretin-induced feeding suppression, suggesting that AgRP neuron inhibition is necessary for the full appetite-suppressing effects of incretin-based therapeutics. Finally, we found that GIP but not GLP-1 is necessary for nutrient-mediated AgRP neuron inhibition, representing a novel physiologic role for GIP in maintaining energy balance. Taken together, these findings reveal neural mechanisms underlying the efficacy of incretin-mimetic obesity therapies. Understanding these drugs' mechanisms of action is crucial for the development of next-generation obesity pharmacotherapies with an improved therapeutic profile.
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Affiliation(s)
- Hayley E McMorrow
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University, Chicago, IL 60611, USA
- Interdepartmental Neuroscience Graduate Program, Northwestern University, Chicago, IL, USA
| | - Carolyn M Lorch
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University, Chicago, IL 60611, USA
- Driskill Graduate Program in Life Sciences, Northwestern University, Chicago, IL, USA
| | - Nikolas W Hayes
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University, Chicago, IL 60611, USA
- Interdepartmental Neuroscience Graduate Program, Northwestern University, Chicago, IL, USA
| | - Stefan W Fleps
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University, Chicago, IL 60611, USA
- Department of Neuroscience, Northwestern University, Chicago, IL, USA
| | - Joshua A Frydman
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Jessica L Xia
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Ricardo J Samms
- Diabetes, Obesity and Complications Therapeutic Area, Eli Lilly, Indianapolis, IN, USA
| | - Lisa R Beutler
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University, Chicago, IL 60611, USA
- Lead contact
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10
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Cao Y, Li R, Bai L. Vagal sensory pathway for the gut-brain communication. Semin Cell Dev Biol 2024; 156:228-243. [PMID: 37558522 DOI: 10.1016/j.semcdb.2023.07.009] [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: 11/21/2022] [Revised: 06/07/2023] [Accepted: 07/20/2023] [Indexed: 08/11/2023]
Abstract
The communication between the gut and brain is crucial for regulating various essential physiological functions, such as energy balance, fluid homeostasis, immune response, and emotion. The vagal sensory pathway plays an indispensable role in connecting the gut to the brain. Recently, our knowledge of the vagal gut-brain axis has significantly advanced through molecular genetic studies, revealing a diverse range of vagal sensory cell types with distinct peripheral innervations, response profiles, and physiological functions. Here, we review the current understanding of how vagal sensory neurons contribute to gut-brain communication. First, we highlight recent transcriptomic and genetic approaches that have characterized different vagal sensory cell types. Then, we focus on discussing how different subtypes encode numerous gut-derived signals and how their activities are translated into physiological and behavioral regulations. The emerging insights into the diverse cell types and functional properties of vagal sensory neurons have paved the way for exciting future directions, which may provide valuable insights into potential therapeutic targets for disorders involving gut-brain communication.
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Affiliation(s)
- Yiyun Cao
- Chinese Institute for Brain Research, Beijing 102206, China
| | - Rui Li
- Chinese Institute for Brain Research, Beijing 102206, China; State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, 100875, China
| | - Ling Bai
- Chinese Institute for Brain Research, Beijing 102206, China.
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11
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Price NL, Fernández-Tussy P, Varela L, Cardelo MP, Shanabrough M, Aryal B, de Cabo R, Suárez Y, Horvath TL, Fernández-Hernando C. microRNA-33 controls hunger signaling in hypothalamic AgRP neurons. Nat Commun 2024; 15:2131. [PMID: 38459068 PMCID: PMC10923783 DOI: 10.1038/s41467-024-46427-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 02/21/2024] [Indexed: 03/10/2024] Open
Abstract
AgRP neurons drive hunger, and excessive nutrient intake is the primary driver of obesity and associated metabolic disorders. While many factors impacting central regulation of feeding behavior have been established, the role of microRNAs in this process is poorly understood. Utilizing unique mouse models, we demonstrate that miR-33 plays a critical role in the regulation of AgRP neurons, and that loss of miR-33 leads to increased feeding, obesity, and metabolic dysfunction in mice. These effects include the regulation of multiple miR-33 target genes involved in mitochondrial biogenesis and fatty acid metabolism. Our findings elucidate a key regulatory pathway regulated by a non-coding RNA that impacts hunger by controlling multiple bioenergetic processes associated with the activation of AgRP neurons, providing alternative therapeutic approaches to modulate feeding behavior and associated metabolic diseases.
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Affiliation(s)
- Nathan L Price
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA
- Yale Center for Molecular and System Metabolism. Yale University School of Medicine, New Haven, CT, USA
- Experimental Gerontology Section, Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Pablo Fernández-Tussy
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA
- Yale Center for Molecular and System Metabolism. Yale University School of Medicine, New Haven, CT, USA
| | - Luis Varela
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA
- Yale Center for Molecular and System Metabolism. Yale University School of Medicine, New Haven, CT, USA
- Laboratory of Glia -Neuron Interactions in the control of Hunger. Achucarro Basque Center for Neuroscience, 48940, Leioa, Vizcaya, Spain
- IKERBASQUE, Basque Foundation for Science, 48009, Bilbao, Vizcaya, Spain
| | - Magdalena P Cardelo
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA
- Yale Center for Molecular and System Metabolism. Yale University School of Medicine, New Haven, CT, USA
| | - Marya Shanabrough
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Binod Aryal
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA
- Yale Center for Molecular and System Metabolism. Yale University School of Medicine, New Haven, CT, USA
| | - Rafael de Cabo
- Experimental Gerontology Section, Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Yajaira Suárez
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA
- Yale Center for Molecular and System Metabolism. Yale University School of Medicine, New Haven, CT, USA
- Department of Pathology. Yale University School of Medicine, New Haven, CT, USA
| | - Tamas L Horvath
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA.
- Yale Center for Molecular and System Metabolism. Yale University School of Medicine, New Haven, CT, USA.
- Laboratory of Glia -Neuron Interactions in the control of Hunger. Achucarro Basque Center for Neuroscience, 48940, Leioa, Vizcaya, Spain.
- IKERBASQUE, Basque Foundation for Science, 48009, Bilbao, Vizcaya, Spain.
- Department of Neuroscience. Yale University School of Medicine, New Haven, CT, USA.
| | - Carlos Fernández-Hernando
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA.
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA.
- Yale Center for Molecular and System Metabolism. Yale University School of Medicine, New Haven, CT, USA.
- Department of Pathology. Yale University School of Medicine, New Haven, CT, USA.
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12
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Fathi PA, Bales MB, Ayala JE. Time dependent changes in feeding behavior and energy balance associated with weight gain in mice fed obesogenic diets. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.10.575043. [PMID: 38260337 PMCID: PMC10802492 DOI: 10.1101/2024.01.10.575043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Obesity is characterized by dysregulated homeostatic mechanisms resulting in positive energy balance, yet when this dysregulation occurs is unknown. We assessed the time course of alterations to behaviors promoting weight gain in male and female mice switched to obesogenic 60% or 45% high fat diet (HFD). Switching mice to obesogenic diets promotes transient bouts of hyperphagia during the first 2 weeks followed by persistent caloric hyperphagia. Energy expenditure increases but not sufficiently to offset increased caloric intake, resulting in a sustained net positive energy balance. Hyperphagia is associated with consumption of calorically larger meals (impaired satiation) more frequently (impaired satiety) particularly during the light-cycle. Running wheel exercise delays weight gain in 60% HFD-fed male mice by enhancing satiation and increasing energy expenditure. However, exercise effects on satiation are no longer apparent after 2 weeks, coinciding with weight gain. Thus, exposure to obesogenic diets engages homeostatic regulatory mechanisms for ∼2 weeks that ultimately fail, and consequent weight gain is characterized by impaired satiation and satiety. Insights into the etiology of obesity can be obtained by investigating changes to satiation and satiety mechanisms during the initial ∼2 weeks of HFD exposure. What is already known about this subject? Obesity is associated with dysregulated homeostatic mechanisms.Increased caloric consumption contributes to obesity.Obese rodents tend to eat larger, more frequent meals. What are the new findings in your manuscript? Exposure to obesogenic diets promotes transient attempts to maintain weight homeostasis.After ∼2 weeks, caloric hyperphagia exceeds increased energy expenditure, promoting weight gain.This is associated with consumption of larger, more frequent meals. How might your results change the direction of research or the focus of clinical practice? Our findings suggest that molecular studies focusing on mechanisms that regulate meal size and frequency, particularly those engaged during the first ∼2 weeks of obesogenic diet feeding that eventually fail, can provide unique insight into the etiology of obesity.
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13
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Goldstein N, Maes A, Allen HN, Nelson TS, Kruger KA, Kindel M, Smith NK, Carty JRE, Villari RE, Cho E, Marble EL, Khanna R, Taylor BK, Kennedy A, Betley JN. A parabrachial hub for the prioritization of survival behavior. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.26.582069. [PMID: 38464066 PMCID: PMC10925167 DOI: 10.1101/2024.02.26.582069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Long-term sustained pain in the absence of acute physical injury is a prominent feature of chronic pain conditions. While neurons responding to noxious stimuli have been identified, understanding the signals that persist without ongoing painful stimuli remains a challenge. Using an ethological approach based on the prioritization of adaptive survival behaviors, we determined that neuropeptide Y (NPY) signaling from multiple sources converges on parabrachial neurons expressing the NPY Y1 receptor to reduce sustained pain responses. Neural activity recordings and computational modeling demonstrate that activity in Y1R parabrachial neurons is elevated following injury, predicts functional coping behavior, and is inhibited by competing survival needs. Taken together, our findings suggest that parabrachial Y1 receptor-expressing neurons are a critical hub for endogenous analgesic pathways that suppress sustained pain states.
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14
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Lorch CM, Hayes NW, Xia JL, Fleps SW, McMorrow HE, Province HS, Frydman JA, Parker JG, Beutler LR. Sucrose overconsumption impairs AgRP neuron dynamics and promotes palatable food intake. Cell Rep 2024; 43:113675. [PMID: 38224492 PMCID: PMC10922425 DOI: 10.1016/j.celrep.2024.113675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 11/17/2023] [Accepted: 01/02/2024] [Indexed: 01/17/2024] Open
Abstract
Rapid gut-brain communication is critical to maintain energy balance and is disrupted in diet-induced obesity. In particular, the role of carbohydrate overconsumption in the regulation of interoceptive circuits in vivo requires further investigation. Here, we report that an obesogenic high-sucrose diet (HSD) selectively blunts silencing of hunger-promoting agouti-related protein (AgRP) neurons following intragastric delivery of glucose, whereas we previously showed that overconsumption of a high-fat diet (HFD) selectively attenuates lipid-induced neural silencing. By contrast, both HSD and HFD reversibly dampen rapid AgRP neuron inhibition following chow presentation and promote intake of more palatable foods. Our findings reveal that excess sugar and fat pathologically modulate feeding circuit activity in both macronutrient-dependent and -independent ways and thus may additively exacerbate obesity.
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Affiliation(s)
- Carolyn M Lorch
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University, Chicago, IL 60611, USA; Driskill Graduate Program in Life Sciences, Northwestern University, Chicago, IL 60611, USA
| | - Nikolas W Hayes
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University, Chicago, IL 60611, USA; Interdepartmental Neuroscience Graduate Program, Northwestern University, Chicago, IL 60611, USA
| | - Jessica L Xia
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Stefan W Fleps
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Neuroscience, Northwestern University, Chicago, IL 60611, USA
| | - Hayley E McMorrow
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University, Chicago, IL 60611, USA; Interdepartmental Neuroscience Graduate Program, Northwestern University, Chicago, IL 60611, USA
| | - Haley S Province
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University, Chicago, IL 60611, USA; Interdepartmental Neuroscience Graduate Program, Northwestern University, Chicago, IL 60611, USA
| | - Joshua A Frydman
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Jones G Parker
- Department of Neuroscience, Northwestern University, Chicago, IL 60611, USA
| | - Lisa R Beutler
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University, Chicago, IL 60611, USA.
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15
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Sayar-Atasoy N, Yavuz Y, Laule C, Dong C, Kim H, Rysted J, Flippo K, Davis D, Aklan I, Yilmaz B, Tian L, Atasoy D. Opioidergic signaling contributes to food-mediated suppression of AgRP neurons. Cell Rep 2024; 43:113630. [PMID: 38165803 PMCID: PMC10865729 DOI: 10.1016/j.celrep.2023.113630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/22/2023] [Accepted: 12/13/2023] [Indexed: 01/04/2024] Open
Abstract
Opioids are generally known to promote hedonic food consumption. Although much of the existing evidence is primarily based on studies of the mesolimbic pathway, endogenous opioids and their receptors are widely expressed in hypothalamic appetite circuits as well; however, their role in homeostatic feeding remains unclear. Using a fluorescent opioid sensor, deltaLight, here we report that mediobasal hypothalamic opioid levels increase by feeding, which directly and indirectly inhibits agouti-related protein (AgRP)-expressing neurons through the μ-opioid receptor (MOR). AgRP-specific MOR expression increases by energy surfeit and contributes to opioid-induced suppression of appetite. Conversely, its antagonists diminish suppression of AgRP neuron activity by food and satiety hormones. Mice with AgRP neuron-specific ablation of MOR expression have increased fat preference without increased motivation. These results suggest that post-ingestion release of endogenous opioids contributes to AgRP neuron inhibition to shape food choice through MOR signaling.
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Affiliation(s)
- Nilufer Sayar-Atasoy
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Yavuz Yavuz
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; Department of Physiology, School of Medicine, Yeditepe University, Istanbul 34755, Turkey
| | - Connor Laule
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Chunyang Dong
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Davis, CA 95616, USA
| | - Hyojin Kim
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Jacob Rysted
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Kyle Flippo
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Debbie Davis
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Iltan Aklan
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Bayram Yilmaz
- Department of Physiology, School of Medicine, Yeditepe University, Istanbul 34755, Turkey
| | - Lin Tian
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Davis, CA 95616, USA
| | - Deniz Atasoy
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; Iowa Neuroscience Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; Fraternal Order of Eagles Diabetes Research Center (FOEDRC), Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
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16
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Andrews ZB. Daily feeding entrains hunger-sensing neurons. Nat Neurosci 2024; 27:10-12. [PMID: 37990115 DOI: 10.1038/s41593-023-01508-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Affiliation(s)
- Zane B Andrews
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia.
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17
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Sayar-Atasoy N, Aklan I, Yavuz Y, Laule C, Kim H, Rysted J, Alp MI, Davis D, Yilmaz B, Atasoy D. AgRP neurons encode circadian feeding time. Nat Neurosci 2024; 27:102-115. [PMID: 37957320 DOI: 10.1038/s41593-023-01482-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 10/05/2023] [Indexed: 11/15/2023]
Abstract
Food intake follows a predictable daily pattern and synchronizes metabolic rhythms. Neurons expressing agouti-related protein (AgRP) read out physiological energetic state and elicit feeding, but the regulation of these neurons across daily timescales is poorly understood. Using a combination of neuron dynamics measurements and timed optogenetic activation in mice, we show that daily AgRP-neuron activity was not fully consistent with existing models of homeostatic regulation. Instead of operating as a 'deprivation counter', AgRP-neuron activity primarily followed the circadian rest-activity cycle through a process that required an intact suprachiasmatic nucleus and synchronization by light. Imposing novel feeding patterns through time-restricted food access or periodic AgRP-neuron stimulation was sufficient to resynchronize the daily AgRP-neuron activity rhythm and drive anticipatory-like behavior through a process that required DMHPDYN neurons. These results indicate that AgRP neurons integrate time-of-day information of past feeding experience with current metabolic needs to predict circadian feeding time.
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Affiliation(s)
- Nilufer Sayar-Atasoy
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA
| | - Iltan Aklan
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA
| | - Yavuz Yavuz
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA
- Department of Physiology, School of Medicine, Yeditepe University, Istanbul, Turkey
| | - Connor Laule
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA
| | - Hyojin Kim
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA
| | - Jacob Rysted
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA
| | - Muhammed Ikbal Alp
- Department of Physiology, School of Medicine, Regenerative and Restorative Medical Research Center (REMER), Istanbul Medipol University, Istanbul, Turkey
| | - Debbie Davis
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA
| | - Bayram Yilmaz
- Department of Physiology, School of Medicine, Yeditepe University, Istanbul, Turkey
| | - Deniz Atasoy
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA.
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA.
- Fraternal Order of Eagles Diabetes Research Center (FOEDRC), Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
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18
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Matiashova L, Hoogkamer AL, Timper K. The Role of the Olfactory System in Obesity and Metabolism in Humans: A Systematic Review and Meta-Analysis. Metabolites 2023; 14:16. [PMID: 38248819 PMCID: PMC10821293 DOI: 10.3390/metabo14010016] [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: 11/29/2023] [Revised: 12/16/2023] [Accepted: 12/20/2023] [Indexed: 01/23/2024] Open
Abstract
Obesity, linked to chronic diseases, poses a global health challenge. While the role of the olfactory system in energy homeostasis is well-documented in rodents, its role in metabolism regulation and obesity in humans remains understudied. This review examines the interplay between olfactory function and metabolic alterations in human obesity and the effects of bariatric surgery on olfactory capabilities in humans. Adhering to PRISMA guidelines, a systematic review and meta-analysis was conducted, focusing exclusively on original human studies. From 51 articles, 14 were selected for the meta-analysis. It was found that variations in olfactory receptor genes influence the susceptibility to odors and predisposition to weight gain and poor eating habits. Bariatric surgery, particularly sleeve gastrectomy, shows significant improvements in olfactory function (SMD 2.37, 95% CI [0.96, 3.77], I = 92%, p = 0.001), especially regarding the olfactory threshold (SMD -1.65, 95% CI [-3.03, -0.27], I = 81%, p = 0.02). There is a bidirectional relationship between olfactory function and metabolism in humans. Bariatric surgery improves olfactory perception in obese patients, but it is still unclear if impacting the olfactory system directly affects eating behavior and the energy balance. However, these findings open novel avenues for future studies addressing the olfactory system as a novel target to alter systemic metabolism in humans.
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Affiliation(s)
- Lolita Matiashova
- Clinic of Endocrinology, Diabetes and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; (A.L.H.); or (K.T.)
| | - Anouk Lisa Hoogkamer
- Clinic of Endocrinology, Diabetes and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; (A.L.H.); or (K.T.)
| | - Katharina Timper
- Clinic of Endocrinology, Diabetes and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; (A.L.H.); or (K.T.)
- Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
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19
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Aitken TJ, Ly T, Shehata S, Sivakumar N, Medina NLS, Gray LA, Dundar N, Barnes C, Knight ZA. Negative feedback control of hunger circuits by the taste of food. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.30.569492. [PMID: 38077047 PMCID: PMC10705440 DOI: 10.1101/2023.11.30.569492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2023]
Abstract
The rewarding taste of food is critical for motivating animals to eat, but whether taste has a parallel function in promoting meal termination is not well understood. Here we show that hunger-promoting AgRP neurons are rapidly inhibited during each bout of ingestion by a signal linked to the taste of food. Blocking these transient dips in activity via closed-loop optogenetic stimulation increases food intake by selectively delaying the onset of satiety. We show that upstream leptin receptor-expressing neurons in the dorsomedial hypothalamus (DMHLepR) are tuned to respond to sweet or fatty tastes and exhibit time-locked activation during feeding that is the mirror image of downstream AgRP cells. These findings reveal an unexpected role for taste in the negative feedback control of ingestion. They also reveal a mechanism by which AgRP neurons, which are the primary cells that drive hunger, are able to influence the moment-by-moment dynamics of food consumption.
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Affiliation(s)
- Tara J Aitken
- Neuroscience Graduate Program, University of California, San Francisco; San Francisco, CA 94158, USA
| | - Truong Ly
- Neuroscience Graduate Program, University of California, San Francisco; San Francisco, CA 94158, USA
| | - Sarah Shehata
- Howard Hughes Medical Institute, University of California, San Francisco; San Francisco, CA 94158, USA
| | - Nilla Sivakumar
- Howard Hughes Medical Institute, University of California, San Francisco; San Francisco, CA 94158, USA
| | - Naymalis La Santa Medina
- Howard Hughes Medical Institute, University of California, San Francisco; San Francisco, CA 94158, USA
| | - Lindsay A Gray
- Howard Hughes Medical Institute, University of California, San Francisco; San Francisco, CA 94158, USA
| | - Naz Dundar
- Neuroscience Graduate Program, University of California, San Francisco; San Francisco, CA 94158, USA
| | - Chris Barnes
- Howard Hughes Medical Institute, University of California, San Francisco; San Francisco, CA 94158, USA
| | - Zachary A Knight
- Department of Physiology, University of California, San Francisco; San Francisco, CA 94158, USA
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco; San Francisco, CA 94158, USA
- Neuroscience Graduate Program, University of California, San Francisco; San Francisco, CA 94158, USA
- Howard Hughes Medical Institute, University of California, San Francisco; San Francisco, CA 94158, USA
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20
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Nyema NT, McKnight AD, Vargas-Elvira AG, Schneps HM, Gold EG, Myers KP, Alhadeff AL. AgRP neuron activity promotes associations between sensory and nutritive signals to guide flavor preference. Mol Metab 2023; 78:101833. [PMID: 37925021 PMCID: PMC10665654 DOI: 10.1016/j.molmet.2023.101833] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 10/20/2023] [Accepted: 10/30/2023] [Indexed: 11/06/2023] Open
Abstract
OBJECTIVE The learned associations between sensory cues (e.g., taste, smell) and nutritive value (e.g., calories, post-ingestive signaling) of foods powerfully influences our eating behavior [1], but the neural circuits that mediate these associations are not well understood. Here, we examined the role of agouti-related protein (AgRP)-expressing neurons - neurons which are critical drivers of feeding behavior [2; 3] - in mediating flavor-nutrient learning (FNL). METHODS Because mice prefer flavors associated with AgRP neuron activity suppression [4], we examined how optogenetic stimulation of AgRP neurons during intake influences FNL, and used fiber photometry to determine how endogenous AgRP neuron activity tracks associations between flavors and nutrients. RESULTS We unexpectedly found that tonic activity in AgRP neurons during FNL potentiated, rather than prevented, the development of flavor preferences. There were notable sex differences in the mechanisms for this potentiation. Specifically, in male mice, AgRP neuron activity increased flavor consumption during FNL training, thereby strengthening the association between flavors and nutrients. In female mice, AgRP neuron activity enhanced flavor-nutrient preferences independently of consumption during training, suggesting that AgRP neuron activity enhances the reward value of the nutrient-paired flavor. Finally, in vivo neural activity analyses demonstrated that acute AgRP neuron dynamics track the association between flavors and nutrients in both sexes. CONCLUSIONS Overall, these data (1) demonstrate that AgRP neuron activity enhances associations between flavors and nutrients in a sex-dependent manner and (2) reveal that AgRP neurons track and rapidly update these associations. Taken together, our findings provide new insight into the role of AgRP neurons in assimilating sensory and nutritive signals for food reinforcement.
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Affiliation(s)
- Nathaniel T Nyema
- Monell Chemical Senses Center, Philadelphia, PA 19104, USA; University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Aaron D McKnight
- Monell Chemical Senses Center, Philadelphia, PA 19104, USA; University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | - Heather M Schneps
- Monell Chemical Senses Center, Philadelphia, PA 19104, USA; University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | | | - Amber L Alhadeff
- Monell Chemical Senses Center, Philadelphia, PA 19104, USA; University of Pennsylvania, Philadelphia, PA 19104, USA.
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21
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So WL, Hu J, Jeffs L, Dempsey H, Lockie SH, Zigman JM, Stark R, Reichenbach A, Andrews ZB. Ghrelin signalling in AgRP neurons links metabolic state to the sensory regulation of AgRP neural activity. Mol Metab 2023; 78:101826. [PMID: 37898450 PMCID: PMC10643323 DOI: 10.1016/j.molmet.2023.101826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 10/11/2023] [Accepted: 10/13/2023] [Indexed: 10/30/2023] Open
Abstract
OBJECTIVE The sensory detection of food and food cues suppresses Agouti related peptide (AgRP) neuronal activity prior to consumption with greatest suppression occurring in response to highly caloric food or interoceptive energy need. However, the interoceptive mechanisms priming an appropriate AgRP neural response to external sensory information of food availability remain unexplored. Since hunger increases plasma ghrelin, we hypothesized that ghrelin receptor (GHSR) signalling on AgRP neurons is a key interoceptive mechanism integrating energy need with external sensory cues predicting caloric availability. METHODS We used in vivo photometry to measure the effects of ghrelin administration or fasting on AgRP neural activity with GCaMP6s and dopamine release in the nucleus accumbens with GRAB-DA in mice lacking ghrelin receptors in AgRP neurons. RESULTS The deletion of GHSR on AgRP neurons prevented ghrelin-induced food intake, motivation and AgRP activity. The presentation of food (peanut butter pellet) or a wooden dowel suppressed AgRP activity in fasted WT but not mice lacking GHSRs in AgRP neurons. Similarly, peanut butter and a wooden dowel increased dopamine release in the nucleus accumbens after ip ghrelin injection in WT but not mice lacking GHSRs in AgRP neurons. No difference in dopamine release was observed in fasted mice. Finally, ip ghrelin administration did not directly increase dopamine neural activity in the ventral tegmental area. CONCLUSIONS Our results suggest that AgRP GHSRs integrate an interoceptive state of energy need with external sensory information to produce an optimal change in AgRP neural activity. Thus, ghrelin signalling on AgRP neurons is more than just a feedback signal to increase AgRP activity during hunger.
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Affiliation(s)
- Wang Lok So
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton 3800, Victoria, Australia
| | - Jiachen Hu
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton 3800, Victoria, Australia
| | - Lotus Jeffs
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton 3800, Victoria, Australia
| | - Harry Dempsey
- The Florey Institute of Neuroscience and Mental Health, Mental Health Division, Parkville, Melbourne, Australia
| | - Sarah H Lockie
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton 3800, Victoria, Australia
| | - Jeffrey M Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA; Division of Endocrinology, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA; Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX, USA
| | - Romana Stark
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton 3800, Victoria, Australia
| | - Alex Reichenbach
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton 3800, Victoria, Australia
| | - Zane B Andrews
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton 3800, Victoria, Australia.
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22
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Aitken CM, Jaramillo JCM, Davis W, Brennan‐Xie L, McDougall SJ, Lawrence AJ, Ryan PJ. Feeding signals inhibit fluid-satiation signals in the mouse lateral parabrachial nucleus to increase intake of highly palatable, caloric solutions. J Neurochem 2023; 167:648-667. [PMID: 37855271 PMCID: PMC10952698 DOI: 10.1111/jnc.15991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 10/01/2023] [Accepted: 10/03/2023] [Indexed: 10/20/2023]
Abstract
Chemogenetic activation of oxytocin receptor-expressing neurons in the parabrachial nucleus (OxtrPBN neurons) acts as a satiation signal for water. In this research, we investigated the effect of activating OxtrPBN neurons on satiation for different types of fluids. Chemogenetic activation of OxtrPBN neurons in male and female transgenic OxtrCre mice robustly suppressed the rapid, initial (15-min) intake of several solutions after dehydration: water, sucrose, ethanol and saccharin, but only slightly decreased intake of Ensure®, a highly caloric solution (1 kcal/mL; containing 3.72 g protein, 3.27 g fat, 13.42 g carbohydrates, and 1.01 g dietary fibre per 100 mL). OxtrPBN neuron activation also suppressed cumulative, longer-term (2-h) intake of lower caloric, less palatable solutions, but not highly caloric, palatable solutions. These results suggest that OxtrPBN neurons predominantly control initial fluid-satiation responses after rehydration, but not longer-term intake of highly caloric, palatable solutions. The suppression of fluid intake was not because of anxiogenesis, but because OxtrPBN neuron activation decreased anxiety-like behaviour. To investigate the role of different PBN subdivisions on the intake of different solutions, we examined FOS as a proxy marker of PBN neuron activation. Different PBN subdivisions were activated by different solutions: the dorsolateral PBN similarly by all fluids; the external lateral PBN by caloric but not non-caloric solutions; and the central lateral PBN primarily by highly palatable solutions, suggesting PBN subdivisions regulate different aspects of fluid intake. To explore the possible mechanisms underlying the minimal suppression of Ensure® after OxtrPBN neuron activation, we demonstrated in in vitro slice recordings that the feeding-associated agouti-related peptide (AgRP) inhibited OxtrPBN neuron firing in a concentration-related manner, suggesting possible inhibition by feeding-related neurocircuitry of fluid satiation neurocircuitry. Overall, this research suggests that although palatable beverages like sucrose- and ethanol-containing beverages activate fluid satiation signals encoded by OxtrPBN neurons, these neurons can be inhibited by hunger-related signals (agouti-related peptide, AgRP), which may explain why these fluids are often consumed in excess of what is required for fluid satiation.
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Affiliation(s)
- Connor M. Aitken
- Florey Institute of Neuroscience & Mental HealthUniversity of MelbourneParkvilleVictoriaAustralia
- Florey Department of Neuroscience & Mental HealthUniversity of MelbourneParkvilleVictoriaAustralia
| | - Janine C. M. Jaramillo
- Florey Institute of Neuroscience & Mental HealthUniversity of MelbourneParkvilleVictoriaAustralia
- Florey Department of Neuroscience & Mental HealthUniversity of MelbourneParkvilleVictoriaAustralia
| | - Warren Davis
- Florey Institute of Neuroscience & Mental HealthUniversity of MelbourneParkvilleVictoriaAustralia
- Florey Department of Neuroscience & Mental HealthUniversity of MelbourneParkvilleVictoriaAustralia
| | - Liam Brennan‐Xie
- Florey Institute of Neuroscience & Mental HealthUniversity of MelbourneParkvilleVictoriaAustralia
| | - Stuart J. McDougall
- Florey Institute of Neuroscience & Mental HealthUniversity of MelbourneParkvilleVictoriaAustralia
| | - Andrew J. Lawrence
- Florey Institute of Neuroscience & Mental HealthUniversity of MelbourneParkvilleVictoriaAustralia
- Florey Department of Neuroscience & Mental HealthUniversity of MelbourneParkvilleVictoriaAustralia
| | - Philip J. Ryan
- Florey Institute of Neuroscience & Mental HealthUniversity of MelbourneParkvilleVictoriaAustralia
- Florey Department of Neuroscience & Mental HealthUniversity of MelbourneParkvilleVictoriaAustralia
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23
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Lai TT, Liou CW, Tsai YH, Lin YY, Wu WL. Butterflies in the gut: the interplay between intestinal microbiota and stress. J Biomed Sci 2023; 30:92. [PMID: 38012609 PMCID: PMC10683179 DOI: 10.1186/s12929-023-00984-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 11/06/2023] [Indexed: 11/29/2023] Open
Abstract
Psychological stress is a global issue that affects at least one-third of the population worldwide and increases the risk of numerous psychiatric disorders. Accumulating evidence suggests that the gut and its inhabiting microbes may regulate stress and stress-associated behavioral abnormalities. Hence, the objective of this review is to explore the causal relationships between the gut microbiota, stress, and behavior. Dysbiosis of the microbiome after stress exposure indicated microbial adaption to stressors. Strikingly, the hyperactivated stress signaling found in microbiota-deficient rodents can be normalized by microbiota-based treatments, suggesting that gut microbiota can actively modify the stress response. Microbiota can regulate stress response via intestinal glucocorticoids or autonomic nervous system. Several studies suggest that gut bacteria are involved in the direct modulation of steroid synthesis and metabolism. This review provides recent discoveries on the pathways by which gut microbes affect stress signaling and brain circuits and ultimately impact the host's complex behavior.
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Affiliation(s)
- Tzu-Ting Lai
- Department of Physiology, College of Medicine, National Cheng Kung University, 1 University Rd., Tainan, 70101, Taiwan
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, 1 University Rd., Tainan, 70101, Taiwan
| | - Chia-Wei Liou
- Department of Physiology, College of Medicine, National Cheng Kung University, 1 University Rd., Tainan, 70101, Taiwan
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, 1 University Rd., Tainan, 70101, Taiwan
| | - Yu-Hsuan Tsai
- Department of Physiology, College of Medicine, National Cheng Kung University, 1 University Rd., Tainan, 70101, Taiwan
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, 1 University Rd., Tainan, 70101, Taiwan
| | - Yuan-Yuan Lin
- Department of Physiology, College of Medicine, National Cheng Kung University, 1 University Rd., Tainan, 70101, Taiwan
| | - Wei-Li Wu
- Department of Physiology, College of Medicine, National Cheng Kung University, 1 University Rd., Tainan, 70101, Taiwan.
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, 1 University Rd., Tainan, 70101, Taiwan.
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24
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Barton JR, Londregan AK, Alexander TD, Entezari AA, Covarrubias M, Waldman SA. Enteroendocrine cell regulation of the gut-brain axis. Front Neurosci 2023; 17:1272955. [PMID: 38027512 PMCID: PMC10662325 DOI: 10.3389/fnins.2023.1272955] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023] Open
Abstract
Enteroendocrine cells (EECs) are an essential interface between the gut and brain that communicate signals about nutrients, pain, and even information from our microbiome. EECs are hormone-producing cells expressed throughout the gastrointestinal epithelium and have been leveraged by pharmaceuticals like semaglutide (Ozempic, Wegovy), terzepatide (Mounjaro), and retatrutide (Phase 2) for diabetes and weight control, and linaclotide (Linzess) to treat irritable bowel syndrome (IBS) and visceral pain. This review focuses on role of intestinal EECs to communicate signals from the gut lumen to the brain. Canonically, EECs communicate information about the intestinal environment through a variety of hormones, dividing EECs into separate classes based on the hormone each cell type secretes. Recent studies have revealed more diverse hormone profiles and communication modalities for EECs including direct synaptic communication with peripheral neurons. EECs known as neuropod cells rapidly relay signals from gut to brain via a direct communication with vagal and primary sensory neurons. Further, this review discusses the complex information processing machinery within EECs, including receptors that transduce intraluminal signals and the ion channel complement that govern initiation and propagation of these signals. Deeper understanding of EEC physiology is necessary to safely treat devastating and pervasive conditions like irritable bowel syndrome and obesity.
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Affiliation(s)
- Joshua R. Barton
- Department of Pharmacology, Physiology, and Cancer Biology, Thomas Jefferson University, Philadelphia, PA, United States
| | - Annie K. Londregan
- Department of Pharmacology, Physiology, and Cancer Biology, Thomas Jefferson University, Philadelphia, PA, United States
| | - Tyler D. Alexander
- Department of Neurosciences, Thomas Jefferson University, Philadelphia, PA, United States
| | - Ariana A. Entezari
- Department of Pharmacology, Physiology, and Cancer Biology, Thomas Jefferson University, Philadelphia, PA, United States
| | - Manuel Covarrubias
- Department of Neurosciences, Thomas Jefferson University, Philadelphia, PA, United States
| | - Scott A. Waldman
- Department of Pharmacology, Physiology, and Cancer Biology, Thomas Jefferson University, Philadelphia, PA, United States
- Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, United States
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25
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Tseng YT, Schaefke B, Wei P, Wang L. Defensive responses: behaviour, the brain and the body. Nat Rev Neurosci 2023; 24:655-671. [PMID: 37730910 DOI: 10.1038/s41583-023-00736-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/11/2023] [Indexed: 09/22/2023]
Abstract
Most animals live under constant threat from predators, and predation has been a major selective force in shaping animal behaviour. Nevertheless, defence responses against predatory threats need to be balanced against other adaptive behaviours such as foraging, mating and recovering from infection. This behavioural balance in ethologically relevant contexts requires adequate integration of internal and external signals in a complex interplay between the brain and the body. Despite this complexity, research has often considered defensive behaviour as entirely mediated by the brain processing threat-related information obtained via perception of the external environment. However, accumulating evidence suggests that the endocrine, immune, gastrointestinal and reproductive systems have important roles in modulating behavioural responses to threat. In this Review, we focus on how predatory threat defence responses are shaped by threat imminence and review the circuitry between subcortical brain regions involved in mediating defensive behaviours. Then, we discuss the intersection of peripheral systems involved in internal states related to infection, hunger and mating with the neurocircuits that underlie defence responses against predatory threat. Through this process, we aim to elucidate the interconnections between the brain and body as an integrated network that facilitates appropriate defensive responses to threat and to discuss the implications for future behavioural research.
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Affiliation(s)
- Yu-Ting Tseng
- CAS Key Laboratory of Brain Connectome and Manipulation, Shenzhen-Hong Kong Institute of Brain Science, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- Guangdong Provincial Key Laboratory of Brain Connectome and Behaviour, the Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Bernhard Schaefke
- CAS Key Laboratory of Brain Connectome and Manipulation, Shenzhen-Hong Kong Institute of Brain Science, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Pengfei Wei
- CAS Key Laboratory of Brain Connectome and Manipulation, Shenzhen-Hong Kong Institute of Brain Science, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Liping Wang
- CAS Key Laboratory of Brain Connectome and Manipulation, Shenzhen-Hong Kong Institute of Brain Science, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
- Guangdong Provincial Key Laboratory of Brain Connectome and Behaviour, the Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
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26
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Reed F, Reichenbach A, Dempsey H, Clarke RE, Mequinion M, Stark R, Rawlinson S, Foldi CJ, Lockie SH, Andrews ZB. Acute inhibition of hunger-sensing AgRP neurons promotes context-specific learning in mice. Mol Metab 2023; 77:101803. [PMID: 37690518 PMCID: PMC10523265 DOI: 10.1016/j.molmet.2023.101803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 08/29/2023] [Accepted: 09/06/2023] [Indexed: 09/12/2023] Open
Abstract
OBJECTIVE An environmental context, which reliably predicts food availability, can increase the appetitive food drive within the same environment context. However, hunger is required for the development of such a context-induced feeding (CIF) response, suggesting the neural circuits sensitive to hunger link an internal energy state with a particular environment context. Since Agouti related peptide (AgRP) neurons are activated by energy deficit, we hypothesised that AgRP neurons are both necessary and sufficient to drive CIF. METHODS To examine the role of AgRP neurons in the CIF process, we used fibre photometry with GCaMP7f, chemogenetic activation of AgRP neurons, as well as optogenetic control of AgRP neurons to facilitate acute temporal control not permitted with chemogenetics. RESULTS A CIF response at test was only observed when mice were fasted during context training and AgRP population activity at test showed an attenuated inhibitory response to food, suggesting increased food-seeking and/or decreased satiety signalling drives the increased feeding response at test. Intriguingly, chemogenetic activation of AgRP neurons during context training did not increase CIF, suggesting precise temporal firing properties may be required. Indeed, termination of AgRP neuronal photostimulation during context training (ON-OFF in context), in the presence or absence of food, increased CIF. Moreover, photoinhibition of AgRP neurons during context training in fasted mice was sufficient to drive a subsequent CIF in the absence of food. CONCLUSIONS Our results suggest that AgRP neurons regulate the acquisition of CIF when the acute inhibition of AgRP activity is temporally matched to context exposure. These results establish acute AgRP inhibition as a salient neural event underscoring the effect of hunger on associative learning.
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Affiliation(s)
- Felicia Reed
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, 3800, Victoria, Australia
| | - Alex Reichenbach
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, 3800, Victoria, Australia
| | - Harry Dempsey
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, 3800, Victoria, Australia
| | - Rachel E Clarke
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Mathieu Mequinion
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, 3800, Victoria, Australia
| | - Romana Stark
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, 3800, Victoria, Australia
| | - Sasha Rawlinson
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, 3800, Victoria, Australia
| | - Claire J Foldi
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, 3800, Victoria, Australia
| | - Sarah H Lockie
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, 3800, Victoria, Australia
| | - Zane B Andrews
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, 3800, Victoria, Australia.
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27
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Gui Y, Dahir NS, Wu Y, Downing G, Sweeney P, Cone RD. Melanocortin-3 receptor expression in AgRP neurons is required for normal activation of the neurons in response to energy deficiency. Cell Rep 2023; 42:113188. [PMID: 37792535 PMCID: PMC10728878 DOI: 10.1016/j.celrep.2023.113188] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 08/14/2023] [Accepted: 09/14/2023] [Indexed: 10/06/2023] Open
Abstract
The melanocortin-3 receptor (MC3R) is a negative regulator of the central melanocortin circuitry via presynaptic expression on agouti-related protein (AgRP) nerve terminals, from where it regulates GABA release onto secondary MC4R-expressing neurons. However, MC3R knockout (KO) mice also exhibit defective behavioral and neuroendocrine responses to fasting. Here, we demonstrate that MC3R KO mice exhibit defective activation of AgRP neurons in response to fasting, cold exposure, or ghrelin while exhibiting normal inhibition of AgRP neurons by sensory detection of food in the ad libitum-fed state. Using a conditional MC3R KO model, we show that the control of AgRP neuron activation by fasting and ghrelin requires the specific presence of MC3R within AgRP neurons. Thus, MC3R is a crucial player in the responsiveness of the AgRP soma to both hormonal and neuronal signals of energy need.
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Affiliation(s)
- Yijun Gui
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109-2216, USA; Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-2216, USA
| | - Naima S Dahir
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109-2216, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109-2216, USA
| | - Yanan Wu
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109-2216, USA; Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-2216, USA
| | - Griffin Downing
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109-2216, USA; Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-2216, USA
| | - Patrick Sweeney
- Department of Molecular and Integrative Physiology, University of Illinois, Urbana-Champaign, IL 61801-3633, USA
| | - Roger D Cone
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109-2216, USA; Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-2216, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109-2216, USA.
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28
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Brüning JC, Fenselau H. Integrative neurocircuits that control metabolism and food intake. Science 2023; 381:eabl7398. [PMID: 37769095 DOI: 10.1126/science.abl7398] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 08/31/2023] [Indexed: 09/30/2023]
Abstract
Systemic metabolism has to be constantly adjusted to the variance of food intake and even be prepared for anticipated changes in nutrient availability. Therefore, the brain integrates multiple homeostatic signals with numerous cues that predict future deviations in energy supply. Recently, our understanding of the neural pathways underlying these regulatory principles-as well as their convergence in the hypothalamus as the key coordinator of food intake, energy expenditure, and glucose metabolism-have been revealed. These advances have changed our view of brain-dependent control of metabolic physiology. In this Review, we discuss new concepts about how alterations in these pathways contribute to the development of prevalent metabolic diseases such as obesity and type 2 diabetes mellitus and how this emerging knowledge may provide new targets for their treatment.
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Affiliation(s)
- Jens C Brüning
- Department of Neuronal Control of Metabolism, Max Planck Institute for Metabolism Research, 50931 Cologne, Germany
- Policlinic for Endocrinology, Diabetes, and Preventive Medicine (PEDP), University Hospital Cologne, 50924 Cologne, Germany
- Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
- National Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Henning Fenselau
- Policlinic for Endocrinology, Diabetes, and Preventive Medicine (PEDP), University Hospital Cologne, 50924 Cologne, Germany
- Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
- Research Group Synaptic Transmission in Energy Homeostasis, Max Planck Institute for Metabolism Research, 50931 Cologne, Germany
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29
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Nyema NT, McKnight AD, Vargas-Elvira AG, Schneps HM, Gold EG, Myers KP, Alhadeff AL. AgRP neuron activity promotes associations between sensory and nutritive signals to guide flavor preference. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.19.558483. [PMID: 37786670 PMCID: PMC10541598 DOI: 10.1101/2023.09.19.558483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
Objective The learned associations between sensory cues (e.g., taste, smell) and nutritive value (e.g., calories, post-ingestive signaling) of foods powerfully influences our eating behavior [1], but the neural circuits that mediate these associations are not well understood. Here, we examined the role of agouti-related protein (AgRP)-expressing neurons - neurons which are critical drivers of feeding behavior [2; 3] - in mediating flavor-nutrient learning (FNL). Methods Because mice prefer flavors associated with AgRP neuron activity suppression [4], we examined how optogenetic stimulation of AgRP neurons during intake influences FNL, and used fiber photometry to determine how endogenous AgRP neuron activity tracks associations between flavors and nutrients. Results We unexpectedly found that tonic activity in AgRP neurons during FNL potentiated, rather than prevented, the development of flavor preferences. There were notable sex differences in the mechanisms for this potentiation. Specifically, in male mice, AgRP neuron activity increased flavor consumption during FNL training, thereby strengthening the association between flavors and nutrients. In female mice, AgRP neuron activity enhanced flavor-nutrient preferences independently of consumption during training, suggesting that AgRP neuron activity enhances the reward value of the nutrient-paired flavor. Finally, in vivo neural activity analyses demonstrated that acute AgRP neuron dynamics track the association between flavors and nutrients in both sexes. Conclusions Overall, these data (1) demonstrate that AgRP neuron activity enhances associations between flavors and nutrients in a sex-dependent manner and (2) reveal that AgRP neurons track and update these associations on fast timescales. Taken together, our findings provide new insight into the role of AgRP neurons in assimilating sensory and nutritive signals for food reinforcement.
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Affiliation(s)
- Nathaniel T. Nyema
- Monell Chemical Senses Center, Philadelphia PA 19104, USA
- University of Pennsylvania, Philadelphia PA 19104, USA
| | - Aaron D. McKnight
- Monell Chemical Senses Center, Philadelphia PA 19104, USA
- University of Pennsylvania, Philadelphia PA 19104, USA
| | | | - Heather M. Schneps
- Monell Chemical Senses Center, Philadelphia PA 19104, USA
- University of Pennsylvania, Philadelphia PA 19104, USA
| | | | | | - Amber L. Alhadeff
- Monell Chemical Senses Center, Philadelphia PA 19104, USA
- University of Pennsylvania, Philadelphia PA 19104, USA
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30
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de Araujo Salgado I, Li C, Burnett CJ, Rodriguez Gonzalez S, Becker JJ, Horvath A, Earnest T, Kravitz AV, Krashes MJ. Toggling between food-seeking and self-preservation behaviors via hypothalamic response networks. Neuron 2023; 111:2899-2917.e6. [PMID: 37442130 PMCID: PMC10528369 DOI: 10.1016/j.neuron.2023.06.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 05/02/2023] [Accepted: 06/15/2023] [Indexed: 07/15/2023]
Abstract
Motivated behaviors are often studied in isolation to assess labeled lines of neural connections underlying innate actions. However, in nature, multiple systems compete for expression of goal-directed behaviors via complex neural networks. Here, we examined flexible survival decisions in animals tasked with food seeking under predation threat. We found that predator exposure rapidly induced physiological, neuronal, and behavioral adaptations in mice highlighted by reduced food seeking and consumption contingent on current threat level. Diminishing conflict via internal state or external environment perturbations shifted feeding strategies. Predator introduction and/or selective manipulation of danger-responsive cholecystokinin (Cck) cells of the dorsal premammilary nucleus (PMd) suppressed hunger-sensitive Agouti-related peptide (AgRP) neurons, providing a mechanism for threat-evoked hypophagia. Increased caloric need enhanced food seeking under duress through AgRP pathways to the bed nucleus of the stria terminalis (BNST) and/or lateral hypothalamus (LH). Our results suggest oscillating interactions between systems underlying self-preservation and food seeking to promote optimal behavior.
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Affiliation(s)
- Isabel de Araujo Salgado
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Chia Li
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - C Joseph Burnett
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Shakira Rodriguez Gonzalez
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jordan J Becker
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Allison Horvath
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Thomas Earnest
- Department of Psychiatry, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Alexxai V Kravitz
- Department of Psychiatry, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Michael J Krashes
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA; National Institute on Drug Abuse (NIDA), National Institutes of Health, Baltimore, MD 21224, USA.
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Cho D, O'Berry K, Possa-Paranhos IC, Butts J, Palanikumar N, Sweeney P. Paraventricular Thalamic MC3R Circuits Link Energy Homeostasis with Anxiety-Related Behavior. J Neurosci 2023; 43:6280-6296. [PMID: 37591737 PMCID: PMC10490510 DOI: 10.1523/jneurosci.0704-23.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 08/03/2023] [Accepted: 08/08/2023] [Indexed: 08/19/2023] Open
Abstract
The hypothalamic melanocortin system is critically involved in sensing stored energy and communicating this information throughout the brain, including to brain regions controlling motivation and emotion. This system consists of first-order agouti-related peptide (AgRP) and pro-opiomelanocortin (POMC) neurons located in the hypothalamic arcuate nucleus and downstream neurons containing the melanocortin-3 (MC3R) and melanocortin-4 receptor (MC4R). Although extensive work has characterized the function of downstream MC4R neurons, the identity and function of MC3R-containing neurons are poorly understood. Here, we used neuroanatomical and circuit manipulation approaches in mice to identify a novel pathway linking hypothalamic melanocortin neurons to melanocortin-3 receptor neurons located in the paraventricular thalamus (PVT) in male and female mice. MC3R neurons in PVT are innervated by hypothalamic AgRP and POMC neurons and are activated by anorexigenic and aversive stimuli. Consistently, chemogenetic activation of PVT MC3R neurons increases anxiety-related behavior and reduces feeding in hungry mice, whereas inhibition of PVT MC3R neurons reduces anxiety-related behavior. These studies position PVT MC3R neurons as important cellular substrates linking energy status with neural circuitry regulating anxiety-related behavior and represent a promising potential target for diseases at the intersection of metabolism and anxiety-related behavior such as anorexia nervosa.SIGNIFICANCE STATEMENT Animals must constantly adapt their behavior to changing internal and external challenges, and impairments in appropriately responding to these challenges are a hallmark of many neuropsychiatric disorders. Here, we demonstrate that paraventricular thalamic neurons containing the melanocortin-3 receptor respond to energy-state-related information and external challenges to regulate anxiety-related behavior in mice. Thus, these neurons represent a potential target for understanding the neurobiology of disorders at the intersection of metabolism and psychiatry such as anorexia nervosa.
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Affiliation(s)
- Dajin Cho
- Department of Molecular and Integrative Physiology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, Illinois 61801
| | - Kyle O'Berry
- Department of Molecular and Integrative Physiology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, Illinois 61801
| | - Ingrid Camila Possa-Paranhos
- Department of Molecular and Integrative Physiology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801
| | - Jared Butts
- Department of Molecular and Integrative Physiology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, Illinois 61801
| | - Naraen Palanikumar
- Department of Molecular and Integrative Physiology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801
| | - Patrick Sweeney
- Department of Molecular and Integrative Physiology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, Illinois 61801
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32
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Hanssen R, Rigoux L, Kuzmanovic B, Iglesias S, Kretschmer AC, Schlamann M, Albus K, Edwin Thanarajah S, Sitnikow T, Melzer C, Cornely OA, Brüning JC, Tittgemeyer M. Liraglutide restores impaired associative learning in individuals with obesity. Nat Metab 2023; 5:1352-1363. [PMID: 37592007 PMCID: PMC10447249 DOI: 10.1038/s42255-023-00859-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 07/07/2023] [Indexed: 08/19/2023]
Abstract
Survival under selective pressure is driven by the ability of our brain to use sensory information to our advantage to control physiological needs. To that end, neural circuits receive and integrate external environmental cues and internal metabolic signals to form learned sensory associations, consequently motivating and adapting our behaviour. The dopaminergic midbrain plays a crucial role in learning adaptive behaviour and is particularly sensitive to peripheral metabolic signals, including intestinal peptides, such as glucagon-like peptide 1 (GLP-1). In a single-blinded, randomized, controlled, crossover basic human functional magnetic resonance imaging study relying on a computational model of the adaptive learning process underlying behavioural responses, we show that adaptive learning is reduced when metabolic sensing is impaired in obesity, as indexed by reduced insulin sensitivity (participants: N = 30 with normal insulin sensitivity; N = 24 with impaired insulin sensitivity). Treatment with the GLP-1 receptor agonist liraglutide normalizes impaired learning of sensory associations in men and women with obesity. Collectively, our findings reveal that GLP-1 receptor activation modulates associative learning in people with obesity via its central effects within the mesoaccumbens pathway. These findings provide evidence for how metabolic signals can act as neuromodulators to adapt our behaviour to our body's internal state and how GLP-1 receptor agonists work in clinics.
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Affiliation(s)
- Ruth Hanssen
- Max Planck Institute for Metabolism Research, Cologne, Germany
- Faculty of Medicine and University Hospital Cologne, Policlinic for Endocrinology, Diabetology and Preventive Medicine (PEPD), University of Cologne, Cologne, Germany
| | - Lionel Rigoux
- Max Planck Institute for Metabolism Research, Cologne, Germany
| | | | - Sandra Iglesias
- Translational Neuromodeling Unit, Institute for Biomedical Engineering, University of Zurich and Swiss Federal Institute of Technology, Zurich, Switzerland
| | - Alina C Kretschmer
- Faculty of Medicine and University Hospital Cologne, Department I of Internal Medicine, Center for Integrated Oncology Aachen Bonn Cologne Duesseldorf (CIO ABCD) and Excellence Center for Medical Mycology (ECMM), University of Cologne, Cologne, Germany
| | - Marc Schlamann
- Faculty of Medicine and University Hospital Cologne, Institute for Diagnostic and Interventional Radiology, University of Cologne, Cologne, Germany
| | - Kerstin Albus
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Sharmili Edwin Thanarajah
- Max Planck Institute for Metabolism Research, Cologne, Germany
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital Frankfurt, Frankfurt am Main, Germany
| | - Tamara Sitnikow
- Faculty of Medicine and University Hospital Cologne, Policlinic for Endocrinology, Diabetology and Preventive Medicine (PEPD), University of Cologne, Cologne, Germany
| | - Corina Melzer
- Max Planck Institute for Metabolism Research, Cologne, Germany
| | - Oliver A Cornely
- Faculty of Medicine and University Hospital Cologne, Department I of Internal Medicine, Center for Integrated Oncology Aachen Bonn Cologne Duesseldorf (CIO ABCD) and Excellence Center for Medical Mycology (ECMM), University of Cologne, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
- German Centre for Infection Research (DZIF), Partner Site Bonn-Cologne, Cologne, Germany
- Faculty of Medicine and University Hospital Cologne, Clinical Trials Centre Cologne (ZKS Köln), University of Cologne, Cologne, Germany
| | - Jens C Brüning
- Max Planck Institute for Metabolism Research, Cologne, Germany
- Faculty of Medicine and University Hospital Cologne, Policlinic for Endocrinology, Diabetology and Preventive Medicine (PEPD), University of Cologne, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Marc Tittgemeyer
- Max Planck Institute for Metabolism Research, Cologne, Germany.
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.
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33
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Haspula D, Cui Z. Neurochemical Basis of Inter-Organ Crosstalk in Health and Obesity: Focus on the Hypothalamus and the Brainstem. Cells 2023; 12:1801. [PMID: 37443835 PMCID: PMC10341274 DOI: 10.3390/cells12131801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 06/23/2023] [Accepted: 07/03/2023] [Indexed: 07/15/2023] Open
Abstract
Precise neural regulation is required for maintenance of energy homeostasis. Essential to this are the hypothalamic and brainstem nuclei which are located adjacent and supra-adjacent to the circumventricular organs. They comprise multiple distinct neuronal populations which receive inputs not only from other brain regions, but also from circulating signals such as hormones, nutrients, metabolites and postprandial signals. Hence, they are ideally placed to exert a multi-tier control over metabolism. The neuronal sub-populations present in these key metabolically relevant nuclei regulate various facets of energy balance which includes appetite/satiety control, substrate utilization by peripheral organs and glucose homeostasis. In situations of heightened energy demand or excess, they maintain energy homeostasis by restoring the balance between energy intake and expenditure. While research on the metabolic role of the central nervous system has progressed rapidly, the neural circuitry and molecular mechanisms involved in regulating distinct metabolic functions have only gained traction in the last few decades. The focus of this review is to provide an updated summary of the mechanisms by which the various neuronal subpopulations, mainly located in the hypothalamus and the brainstem, regulate key metabolic functions.
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Affiliation(s)
- Dhanush Haspula
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Zhenzhong Cui
- Mouse Metabolism Core, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA;
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34
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Becetti I, Bwenyi EL, de Araujo IE, Ard J, Cryan JF, Farooqi IS, Ferrario CR, Gluck ME, Holsen LM, Kenny PJ, Lawson EA, Lowell BB, Schur EA, Stanley TL, Tavakkoli A, Grinspoon SK, Singhal V. The Neurobiology of Eating Behavior in Obesity: Mechanisms and Therapeutic Targets: A Report from the 23rd Annual Harvard Nutrition Obesity Symposium. Am J Clin Nutr 2023; 118:314-328. [PMID: 37149092 PMCID: PMC10375463 DOI: 10.1016/j.ajcnut.2023.05.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 04/03/2023] [Accepted: 05/01/2023] [Indexed: 05/08/2023] Open
Abstract
Obesity is increasing at an alarming rate. The effectiveness of currently available strategies for the treatment of obesity (including pharmacologic, surgical, and behavioral interventions) is limited. Understanding the neurobiology of appetite and the important drivers of energy intake (EI) can lead to the development of more effective strategies for the prevention and treatment of obesity. Appetite regulation is complex and is influenced by genetic, social, and environmental factors. It is intricately regulated by a complex interplay of endocrine, gastrointestinal, and neural systems. Hormonal and neural signals generated in response to the energy state of the organism and the quality of food eaten are communicated by paracrine, endocrine, and gastrointestinal signals to the nervous system. The central nervous system integrates homeostatic and hedonic signals to regulate appetite. Although there has been an enormous amount of research over many decades regarding the regulation of EI and body weight, research is only now yielding potentially effective treatment strategies for obesity. The purpose of this article is to summarize the key findings presented in June 2022 at the 23rd annual Harvard Nutrition Obesity Symposium entitled "The Neurobiology of Eating Behavior in Obesity: Mechanisms and Therapeutic Targets." Findings presented at the symposium, sponsored by NIH P30 Nutrition Obesity Research Center at Harvard, enhance our current understanding of appetite biology, including innovative techniques used to assess and systematically manipulate critical hedonic processes, which will shape future research and the development of therapeutics for obesity prevention and treatment.
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Affiliation(s)
- Imen Becetti
- Division of Pediatric Endocrinology, Massachusetts General Hospital for Children and Harvard Medical School, Boston, MA, United States.
| | - Esther L Bwenyi
- Metabolism Unit, Massachusetts General Hospital, Boston, MA, United States; Nutrition Obesity Research Center at Harvard Medical School, Massachusetts General Hospital, Boston, MA, United States
| | - Ivan E de Araujo
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York City, NY, United States; Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York City, NY, United States
| | - Jamy Ard
- Epidemiology and Prevention, Wake Forest University School of Medicine, Winston-Salem, NC, United States; Bariatric and Weight Management Center, Wake Forest Baptist Health, Winston-Salem, NC, United States; Center on Diabetes, Obesity, and Metabolism, Wake Forest University School of Medicine, Winston-Salem, NC, United States; Sticht Center for Healthy Aging and Alzheimer's Prevention, Wake Forest University School of Medicine, Winston-Salem, NC, United States; Hypertension and Vascular Research Center, Cardiovascular Sciences Center, Wake Forest University School of Medicine, Winston-Salem, NC, United States; Maya Angelou Center for Healthy Equity, Wake Forest University School of Medicine, Winston-Salem, NC, United States
| | - John F Cryan
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Ismaa Sadaf Farooqi
- University of Cambridge Metabolic Research Laboratories and National Institute for Health and Care Research (NIHR) Cambridge Biomedical Research Centre, University of Cambridge, Cambridge, United Kingdom; Wellcome-Medical Research Council (MRC) Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom; Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, United Kingdom
| | - Carrie R Ferrario
- Department of Pharmacology, Psychology Department (Biopsychology Area), University of Michigan, Ann Arbor, MI, United States
| | - Marci E Gluck
- National Institutes of Health, Phoenix, AZ, United States; National Institute of Diabetes and Digestive and Kidney Disease, Obesity and Diabetes Clinical Research Section, Phoenix Epidemiology and Clinical Research Branch, Phoenix, AZ, United States
| | - Laura M Holsen
- Harvard Medical School, Boston, MA, United States; Division of Women's Health, Department of Medicine, Brigham and Women's Hospital, Boston, MA, United States; Department of Psychiatry, Brigham and Women's Hospital, Boston, MA, United States
| | - Paul J Kenny
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York City, NY, United States; Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York City, NY, United States
| | - Elizabeth A Lawson
- Nutrition Obesity Research Center at Harvard Medical School, Massachusetts General Hospital, Boston, MA, United States; Department of Medicine, Harvard Medical School, Boston, MA, United States; Neuroendocrine Unit, Massachusetts General Hospital, Boston, MA, United States
| | - Bradford B Lowell
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States
| | - Ellen A Schur
- Division of General Internal Medicine, University of Washington, Seattle, WA, United States; Univeristy of Washington Medicine Diabetes Institute, University of Washington, Seattle, WA, United States; Univeristy of Washington Nutrition and Obesity Research Center, University of Washington, Seattle, WA, United States; Clinical and Translational Research Services Core, University of Washington, Seattle, WA, United States
| | - Takara L Stanley
- Division of Pediatric Endocrinology, Massachusetts General Hospital for Children and Harvard Medical School, Boston, MA, United States; Metabolism Unit, Massachusetts General Hospital, Boston, MA, United States; Nutrition Obesity Research Center at Harvard Medical School, Massachusetts General Hospital, Boston, MA, United States; Harvard Medical School, Boston, MA, United States
| | - Ali Tavakkoli
- Division of General and Gastrointestinal (GI) Surgery, Center for Weight Management and Wellness, Advanced Minimally Invasive Fellowship, Harvard Medical School, Boston, MA, United States
| | - Steven K Grinspoon
- Metabolism Unit, Massachusetts General Hospital, Boston, MA, United States; Nutrition Obesity Research Center at Harvard Medical School, Massachusetts General Hospital, Boston, MA, United States; Harvard Medical School, Boston, MA, United States; Department of Medicine, Harvard Medical School, Boston, MA, United States
| | - Vibha Singhal
- Division of Pediatric Endocrinology, Massachusetts General Hospital for Children and Harvard Medical School, Boston, MA, United States; Harvard Medical School, Boston, MA, United States; Pediatric Endocrinology and Obesity Medicine, Massachusetts General Hospital, Boston, MA, United States; Pediatric Program MGH Weight Center, Massachusetts General Hospital, Boston, MA, United States
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35
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Gui Y, Dahir NS, Downing G, Sweeney P, Cone RD. Cell autonomous regulation of the activation of AgRP neurons by the melanocortin-3 receptor. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.28.546874. [PMID: 37425887 PMCID: PMC10327035 DOI: 10.1101/2023.06.28.546874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
The melanocortin-3 receptor (MC3R) is a negative regulator of the central melanocortin circuitry via presynaptic expression on AgRP nerve terminals, from where it regulates GABA release onto secondary MC4R-expressing neurons. Hence, animals lacking MC3R (MC3R KO) exhibit hypersensitivity to MC4R agonists. However, MC3R KO mice also exhibit defective behavioral and neuroendocrine responses to fasting. Here, we demonstrate that MC3R KO mice exhibit defective activation of AgRP neurons in response to fasting and cold exposure, while exhibiting normal inhibition of AgRP neurons by sensory detection of food. Further, using an AgRP-specific MC3R knockout model, we show that the control of AgRP neuron activation by MC3R is cell-autonomous. One mechanism underlying this involves the response to ghrelin, which is also blunted in mice with AgRP-specific deletion of the MC3R. Thus, MC3R is a crucial player in the control of energy homeostasis by the central melanocortin system, not only acting presynaptically on AgRP neurons, but via AgRP cell-autonomous regulation of fasting- and cold-induced neuronal activation as well.
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36
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van Galen KA, Schrantee A, Ter Horst KW, la Fleur SE, Booij J, Constable RT, Schwartz GJ, DiLeone RJ, Serlie MJ. Brain responses to nutrients are severely impaired and not reversed by weight loss in humans with obesity: a randomized crossover study. Nat Metab 2023:10.1038/s42255-023-00816-9. [PMID: 37308722 DOI: 10.1038/s42255-023-00816-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Accepted: 05/04/2023] [Indexed: 06/14/2023]
Abstract
Post-ingestive nutrient signals to the brain regulate eating behaviour in rodents, and impaired responses to these signals have been associated with pathological feeding behaviour and obesity. To study this in humans, we performed a single-blinded, randomized, controlled, crossover study in 30 humans with a healthy body weight (females N = 12, males N = 18) and 30 humans with obesity (females N = 18, males N = 12). We assessed the effect of intragastric glucose, lipid and water (noncaloric isovolumetric control) infusions on the primary endpoints cerebral neuronal activity and striatal dopamine release, as well as on the secondary endpoints plasma hormones and glucose, hunger scores and caloric intake. To study whether impaired responses in participants with obesity would be partially reversible with diet-induced weight loss, imaging was repeated after 10% diet-induced weight loss. We show that intragastric glucose and lipid infusions induce orosensory-independent and preference-independent, nutrient-specific cerebral neuronal activity and striatal dopamine release in lean participants. In contrast, participants with obesity have severely impaired brain responses to post-ingestive nutrients. Importantly, the impaired neuronal responses are not restored after diet-induced weight loss. Impaired neuronal responses to nutritional signals may contribute to overeating and obesity, and ongoing resistance to post-ingestive nutrient signals after significant weight loss may in part explain the high rate of weight regain after successful weight loss.
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Affiliation(s)
- Katy A van Galen
- Amsterdam UMC, location AMC, Department of Radiology and Nuclear Medicine, Amsterdam, the Netherlands
| | - Anouk Schrantee
- Amsterdam UMC, location AMC, Department of Radiology and Nuclear Medicine, Amsterdam, the Netherlands
| | - Kasper W Ter Horst
- Amsterdam University Medical Centers (UMC), location AMC, Department of Endocrinology and Metabolism and Amsterdam Gastroenterology Metabolism Endocrinology Institute, Amsterdam, the Netherlands
| | - Susanne E la Fleur
- Amsterdam University Medical Centers (UMC), location AMC, Department of Endocrinology and Metabolism and Amsterdam Gastroenterology Metabolism Endocrinology Institute, Amsterdam, the Netherlands
- Amsterdam UMC, location AMC, Department of Clinical Chemistry, Laboratory of Endocrinology, Amsterdam, the Netherlands
| | - Jan Booij
- Amsterdam UMC, location AMC, Department of Radiology and Nuclear Medicine, Amsterdam, the Netherlands
| | - R Todd Constable
- Yale University School of Medicine, Department of Radiology and Biomedical Imaging, New Haven, CT, USA
| | - Gary J Schwartz
- Albert Einstein College of Medicine, Fleischer Institute for Diabetes and Metabolism, Bronx, NY, USA
| | - Ralph J DiLeone
- Yale University School of Medicine, Department of Psychiatry, New Haven, CT, USA
| | - Mireille J Serlie
- Amsterdam University Medical Centers (UMC), location AMC, Department of Endocrinology and Metabolism and Amsterdam Gastroenterology Metabolism Endocrinology Institute, Amsterdam, the Netherlands.
- Yale University School of Medicine, Department of Endocrinology, New Haven, CT, USA.
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37
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López M, Fernández-Real JM, Tomarev SI. Obesity wars: may the smell be with you. Am J Physiol Endocrinol Metab 2023; 324:E569-E576. [PMID: 37166265 PMCID: PMC10259866 DOI: 10.1152/ajpendo.00040.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 05/08/2023] [Accepted: 05/09/2023] [Indexed: 05/12/2023]
Abstract
Classically, the regulation of energy balance has been based on central and peripheral mechanisms sensing energy, nutrients, metabolites, and hormonal cues. Several cellular mechanisms at central level, such as hypothalamic AMP-activated protein kinase (AMPK), integrate this information to elicit counterregulatory responses that control feeding, energy expenditure, and glucose homeostasis, among other processes. Recent data have added more complexity to the homeostatic regulation of metabolism by introducing, for example, the key role of "traditional" senses and sensorial information in this complicated network. In this regard, current evidence is showing that olfaction plays a key and bidirectional role in energy homeostasis. Although nutritional status dynamically and profoundly impacts olfactory sensitivity, the sense of smell is involved in food appreciation and selection, as well as in brown adipose tissue (BAT) thermogenesis and substrate utilization, with some newly described actors, such as olfactomedin 2 (OLFM2), likely playing a major role. Thus, olfactory inputs are contributing to the regulation of both sides of the energy balance equation, namely, feeding and energy expenditure (EE), as well as whole body metabolism. Here, we will review the current knowledge and advances about the role of olfaction in the regulation of energy homeostasis.
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Affiliation(s)
- Miguel López
- NeurObesity Group, Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Spain
| | - José Manuel Fernández-Real
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Spain
- Service of Diabetes, Endocrinology and Nutrition (UDEN), Institut d'Investigació Biomédica de Girona (IDIBGI), Department of Medical Sciences, University of Girona, Girona, Spain
| | - Stanislav I Tomarev
- Section of Retinal Ganglion Cell Biology, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
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38
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Grzelka K, Wilhelms H, Dodt S, Dreisow ML, Madara JC, Walker SJ, Wu C, Wang D, Lowell BB, Fenselau H. A synaptic amplifier of hunger for regaining body weight in the hypothalamus. Cell Metab 2023; 35:770-785.e5. [PMID: 36965483 PMCID: PMC10160008 DOI: 10.1016/j.cmet.2023.03.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 12/15/2022] [Accepted: 03/01/2023] [Indexed: 03/27/2023]
Abstract
Restricting caloric intake effectively reduces body weight, but most dieters fail long-term adherence to caloric deficit and eventually regain lost weight. Hypothalamic circuits that control hunger drive critically determine body weight; yet, how weight loss sculpts these circuits to motivate food consumption until lost weight is regained remains unclear. Here, we probe the contribution of synaptic plasticity in discrete excitatory afferents on hunger-promoting AgRP neurons. We reveal a crucial role for activity-dependent, remarkably long-lasting amplification of synaptic activity originating from paraventricular hypothalamus thyrotropin-releasing (PVHTRH) neurons in long-term body weight control. Silencing PVHTRH neurons inhibits the potentiation of excitatory input to AgRP neurons and diminishes concomitant regain of lost weight. Brief stimulation of the pathway is sufficient to enduringly potentiate this glutamatergic hunger synapse and triggers an NMDAR-dependent gaining of body weight that enduringly persists. Identification of this activity-dependent synaptic amplifier provides a previously unrecognized target to combat regain of lost weight.
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Affiliation(s)
- Katarzyna Grzelka
- Synaptic Transmission in Energy Homeostasis Group, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany
| | - Hannah Wilhelms
- Synaptic Transmission in Energy Homeostasis Group, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany
| | - Stephan Dodt
- Synaptic Transmission in Energy Homeostasis Group, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany; Department of Neuronal Control of Metabolism, Max Planck Institute for Metabolism Research, Cologne, Germany
| | - Marie-Luise Dreisow
- Synaptic Transmission in Energy Homeostasis Group, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany
| | - Joseph C Madara
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Samuel J Walker
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Chen Wu
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Daqing Wang
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Bradford B Lowell
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA; Program in Neuroscience, Harvard Medical School, Boston, MA 02215, USA.
| | - Henning Fenselau
- Synaptic Transmission in Energy Homeostasis Group, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany; Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Kerpener Strasse 26, 50924 Cologne, Germany; Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, Joseph-Stelzmann-Straße 26, Cologne 50931, Germany.
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39
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Sutton Hickey AK, Duane SC, Mickelsen LE, Karolczak EO, Shamma AM, Skillings A, Li C, Krashes MJ. AgRP neurons coordinate the mitigation of activity-based anorexia. Mol Psychiatry 2023; 28:1622-1635. [PMID: 36577844 PMCID: PMC10782560 DOI: 10.1038/s41380-022-01932-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 12/13/2022] [Accepted: 12/14/2022] [Indexed: 12/29/2022]
Abstract
Anorexia nervosa (AN) is a debilitating and deadly disease characterized by low body mass index due to diminished food intake, and oftentimes concurrent hyperactivity. A high percentage of AN behavioral and metabolic phenotypes can be replicated in rodents given access to a voluntary running wheel and subject to food restriction, termed activity-based anorexia (ABA). Despite the well-documented bodyweight loss observed in AN human patients and ABA rodents, much less is understood regarding the neurobiological underpinnings of these maladaptive behaviors. Hunger-promoting hypothalamic agouti-related peptide (AgRP) neurons have been well characterized in their ability to regulate appetite, yet much less is known regarding their activity and function in the mediation of food intake during ABA. Here, feeding microstructure analysis revealed ABA mice decreased food intake due to increased interpellet interval retrieval and diminished meal number. Longitudinal activity recordings of AgRP neurons in ABA animals exhibited a maladaptive inhibitory response to food, independent of basal activity changes. We then demonstrated that ABA development or progression can be mitigated by chemogenetic AgRP activation through the reprioritization of food intake (increased meal number) over hyperactivity, but only during periods of food availability. These results elucidate a potential neural target for the amelioration of behavioral maladaptations present in AN patients.
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Affiliation(s)
- Ames K Sutton Hickey
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, USA.
| | - Sean C Duane
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, USA
| | - Laura E Mickelsen
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, USA
| | - Eva O Karolczak
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, USA
| | - Ahmed M Shamma
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, USA
| | - Anna Skillings
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, USA
| | - Chia Li
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, USA
| | - Michael J Krashes
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, USA.
- National Institute on Drug Abuse (NIDA), National Institutes of Health, Baltimore, MD, USA.
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Kuang D, Hanchate NK, Lee CY, Heck A, Ye X, Erdenebileg M, Buck LB. Olfactory and neuropeptide inputs to appetite neurons in the arcuate nucleus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.28.530282. [PMID: 36909633 PMCID: PMC10002664 DOI: 10.1101/2023.02.28.530282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
The sense of smell has potent effects on appetite, but the underlying neural mechanisms are largely a mystery. The hypothalamic arcuate nucleus contains two subsets of neurons linked to appetite: AgRP (agouti-related peptide) neurons, which enhance appetite, and POMC (pro-opiomelanocortin) neurons, which suppress appetite. Here, we find that AgRP and POMC neurons receive indirect inputs from partially overlapping areas of the olfactory cortex, thus identifying their sources of odor signals. We also find neurons directly upstream of AgRP or POMC neurons in numerous other areas, identifying potential relays between the olfactory cortex and AgRP or POMC neurons. Transcriptome profiling of individual AgRP neurons reveals differential expression of receptors for multiple neuromodulators. Notably, known ligands of the receptors define subsets of neurons directly upstream of AgRP neurons in specific brain areas. Together, these findings indicate that higher olfactory areas can differentially influence AgRP and POMC appetite neurons, that subsets of AgRP neurons can be regulated by different neuromodulators, and that subsets of neurons upstream of AgRP neurons in specific brain areas use different neuromodulators, together or in distinct combinations to modulate AgRP neurons and thus appetite.
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Dohnalová L, Lundgren P, Carty JRE, Goldstein N, Wenski SL, Nanudorn P, Thiengmag S, Huang KP, Litichevskiy L, Descamps HC, Chellappa K, Glassman A, Kessler S, Kim J, Cox TO, Dmitrieva-Posocco O, Wong AC, Allman EL, Ghosh S, Sharma N, Sengupta K, Cornes B, Dean N, Churchill GA, Khurana TS, Sellmyer MA, FitzGerald GA, Patterson AD, Baur JA, Alhadeff AL, Helfrich EJN, Levy M, Betley JN, Thaiss CA. A microbiome-dependent gut-brain pathway regulates motivation for exercise. Nature 2022; 612:739-747. [PMID: 36517598 PMCID: PMC11162758 DOI: 10.1038/s41586-022-05525-z] [Citation(s) in RCA: 79] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 11/04/2022] [Indexed: 12/16/2022]
Abstract
Exercise exerts a wide range of beneficial effects for healthy physiology1. However, the mechanisms regulating an individual's motivation to engage in physical activity remain incompletely understood. An important factor stimulating the engagement in both competitive and recreational exercise is the motivating pleasure derived from prolonged physical activity, which is triggered by exercise-induced neurochemical changes in the brain. Here, we report on the discovery of a gut-brain connection in mice that enhances exercise performance by augmenting dopamine signalling during physical activity. We find that microbiome-dependent production of endocannabinoid metabolites in the gut stimulates the activity of TRPV1-expressing sensory neurons and thereby elevates dopamine levels in the ventral striatum during exercise. Stimulation of this pathway improves running performance, whereas microbiome depletion, peripheral endocannabinoid receptor inhibition, ablation of spinal afferent neurons or dopamine blockade abrogate exercise capacity. These findings indicate that the rewarding properties of exercise are influenced by gut-derived interoceptive circuits and provide a microbiome-dependent explanation for interindividual variability in exercise performance. Our study also suggests that interoceptomimetic molecules that stimulate the transmission of gut-derived signals to the brain may enhance the motivation for exercise.
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Affiliation(s)
- Lenka Dohnalová
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Obesity, Diabetes and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Molecular Bio Science, Goethe University Frankfurt, and LOEWE Center for Translational Biodiversity Genomics, Frankfurt, Germany
| | - Patrick Lundgren
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Obesity, Diabetes and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jamie R E Carty
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Nitsan Goldstein
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Sebastian L Wenski
- Institute for Molecular Bio Science, Goethe University Frankfurt, and LOEWE Center for Translational Biodiversity Genomics, Frankfurt, Germany
| | - Pakjira Nanudorn
- Institute for Molecular Bio Science, Goethe University Frankfurt, and LOEWE Center for Translational Biodiversity Genomics, Frankfurt, Germany
| | - Sirinthra Thiengmag
- Institute for Molecular Bio Science, Goethe University Frankfurt, and LOEWE Center for Translational Biodiversity Genomics, Frankfurt, Germany
| | | | - Lev Litichevskiy
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Obesity, Diabetes and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Hélène C Descamps
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Obesity, Diabetes and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Karthikeyani Chellappa
- Institute for Obesity, Diabetes and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Ana Glassman
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Obesity, Diabetes and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Susanne Kessler
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Obesity, Diabetes and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jihee Kim
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Obesity, Diabetes and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Timothy O Cox
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Obesity, Diabetes and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Oxana Dmitrieva-Posocco
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Andrea C Wong
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Erik L Allman
- Department of Biochemistry and Molecular Biology and Department of Veterinary and Biomedical Sciences, the Pennsylvania State University, University Park, PA, USA
| | - Soumita Ghosh
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Nitika Sharma
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Kasturi Sengupta
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | | | | | | | - Tejvir S Khurana
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Mark A Sellmyer
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Garret A FitzGerald
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Andrew D Patterson
- Department of Biochemistry and Molecular Biology and Department of Veterinary and Biomedical Sciences, the Pennsylvania State University, University Park, PA, USA
| | - Joseph A Baur
- Institute for Obesity, Diabetes and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Amber L Alhadeff
- Monell Chemical Senses Center, Philadelphia, PA, USA
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Eric J N Helfrich
- Institute for Molecular Bio Science, Goethe University Frankfurt, and LOEWE Center for Translational Biodiversity Genomics, Frankfurt, Germany
| | - Maayan Levy
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - J Nicholas Betley
- Institute for Obesity, Diabetes and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Christoph A Thaiss
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Institute for Obesity, Diabetes and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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Abstract
When it comes to food, one tempting substance is sugar. Although sweetness is detected by the tongue, the desire to consume sugar arises from the gut. Even when sweet taste is impaired, animals can distinguish sugars from non-nutritive sweeteners guided by sensory cues arising from the gut epithelium. Here, we review the molecular receptors, cells, circuits and behavioural consequences associated with sugar sensing in the gut. Recent work demonstrates that some duodenal cells, termed neuropod cells, can detect glucose using sodium-glucose co-transporter 1 and release glutamate onto vagal afferent neurons. Based on these and other data, we propose a model in which specific populations of vagal neurons relay these sensory cues to distinct sets of neurons in the brain, including neurons in the caudal nucleus of the solitary tract, dopaminergic reward circuits in the basal ganglia and homeostatic feeding circuits in the hypothalamus, that alter current and future sugar consumption. This emerging model highlights the critical role of the gut in sensing the chemical properties of ingested nutrients to guide appetitive decisions.
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Affiliation(s)
- Winston W Liu
- Laboratory of Gut Brain Neurobiology, Duke University, Durham, NC, USA
- Department of Medicine, Duke University, Durham, NC, USA
- Department of Neurobiology, Duke University, Durham, NC, USA
| | - Diego V Bohórquez
- Laboratory of Gut Brain Neurobiology, Duke University, Durham, NC, USA.
- Department of Medicine, Duke University, Durham, NC, USA.
- Department of Neurobiology, Duke University, Durham, NC, USA.
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Boutagouga Boudjadja M, Culotta I, De Paula GC, Harno E, Hunter J, Cavalcanti-de-Albuquerque JP, Luckman SM, Hepworth M, White A, Aviello G, D'Agostino G. Hypothalamic AgRP neurons exert top-down control on systemic TNF-α release during endotoxemia. Curr Biol 2022; 32:4699-4706.e4. [PMID: 36182699 DOI: 10.1016/j.cub.2022.09.017] [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: 05/16/2022] [Revised: 07/21/2022] [Accepted: 09/08/2022] [Indexed: 11/25/2022]
Abstract
Loss of appetite and negative energy balance are common features of endotoxemia in all animals and are thought to have protective roles by reducing nutrient availability to host and pathogen metabolism. Accordingly, fasting and caloric restriction have well-established anti-inflammatory properties. However, in response to reduced nutrient availability at the cellular and organ levels, negative energy balance also recruits distinct energy-sensing brain circuits, but it is not known whether these neuronal systems have a role in its anti-inflammatory effects. Here, we report that hypothalamic AgRP neurons-a critical neuronal population for the central representation of negative energy balance-have parallel immunoregulatory functions. We found that when endotoxemia occurs in fasted mice, the activity of AgRP neurons remains sustained, but this activity does not influence feeding behavior and endotoxemic anorexia. Furthermore, we found that endotoxemia acutely desensitizes AgRP neurons, which also become refractory to inhibitory signals. Mimicking this sustained AgRP neuron activity in fed mice by chemogenetic activation-a manipulation known to recapitulate core behavioral features of fasting-results in reduced acute tumor necrosis factor alpha (TNF-α) release during endotoxemia. Mechanistically, we found that endogenous glucocorticoids play an important role: glucocorticoid receptor deletion from AgRP neurons prevents their endotoxemia-induced desensitization, and importantly, it counteracts the fasting-induced suppression of TNF-α release, resulting in prolonged sickness. Together, these findings provide evidence directly linking AgRP neuron activity to the acute response during endotoxemia, suggesting that these neurons are a functional component of the immunoregulatory effects associated with negative energy balance and catabolic metabolism.
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Affiliation(s)
- Mehdi Boutagouga Boudjadja
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK; The Rowett Institute, University of Aberdeen, Aberdeen, UK
| | - Isabella Culotta
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | | | - Erika Harno
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Jenna Hunter
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | | | - Simon M Luckman
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Matthew Hepworth
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Anne White
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Gabriella Aviello
- The Rowett Institute, University of Aberdeen, Aberdeen, UK; Department of Pharmacy, University of Naples Federico II, Naples, Italy
| | - Giuseppe D'Agostino
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK; The Rowett Institute, University of Aberdeen, Aberdeen, UK.
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Hwang E, Scarlett JM, Baquero AF, Bennett CM, Dong Y, Chau D, Brown JM, Mercer AJ, Meek TH, Grove KL, Phan BAN, Morton GJ, Williams KW, Schwartz MW. Sustained inhibition of NPY/AgRP neuronal activity by FGF1. JCI Insight 2022; 7:e160891. [PMID: 35917179 PMCID: PMC9536267 DOI: 10.1172/jci.insight.160891] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 07/27/2022] [Indexed: 11/17/2022] Open
Abstract
In rodent models of type 2 diabetes (T2D), central administration of FGF1 normalizes elevated blood glucose levels in a manner that is sustained for weeks or months. Increased activity of NPY/AgRP neurons in the hypothalamic arcuate nucleus (ARC) is implicated in the pathogenesis of hyperglycemia in these animals, and the ARC is a key brain area for the antidiabetic action of FGF1. We therefore sought to determine whether FGF1 inhibits NPY/AgRP neurons and, if so, whether this inhibitory effect is sufficiently durable to offer a feasible explanation for sustained diabetes remission induced by central administration of FGF1. Here, we show that FGF1 inhibited ARC NPY/AgRP neuron activity, both after intracerebroventricular injection in vivo and when applied ex vivo in a slice preparation; we also showed that the underlying mechanism involved increased input from presynaptic GABAergic neurons. Following central administration, the inhibitory effect of FGF1 on NPY/AgRP neurons was also highly durable, lasting for at least 2 weeks. To our knowledge, no precedent for such a prolonged inhibitory effect exists. Future studies are warranted to determine whether NPY/AgRP neuron inhibition contributes to the sustained antidiabetic action elicited by intracerebroventricular FGF1 injection in rodent models of T2D.
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Affiliation(s)
- Eunsang Hwang
- Department of Internal Medicine, Center for Hypothalamic Research, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA
| | - Jarrad M. Scarlett
- Department of Medicine, University of Washington Medicine Diabetes Institute, Seattle, Washington, USA
- Department of Pediatric Gastroenterology and Hepatology, Seattle Children’s Hospital, Seattle, Washington, USA
| | - Arian F. Baquero
- Obesity Research, Novo Nordisk Research Center Seattle, Seattle, Washington, USA
| | - Camdin M. Bennett
- Obesity Research, Novo Nordisk Research Center Seattle, Seattle, Washington, USA
| | - Yanbin Dong
- Department of Internal Medicine, Center for Hypothalamic Research, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA
| | - Dominic Chau
- Department of Internal Medicine, Center for Hypothalamic Research, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA
| | - Jenny M. Brown
- Department of Medicine, University of Washington Medicine Diabetes Institute, Seattle, Washington, USA
- University of Copenhagen, Novo Nordisk Foundation Center for Basic Metabolic Research, Copenhagen, Denmark
| | - Aaron J. Mercer
- Obesity Research, Novo Nordisk Research Center Seattle, Seattle, Washington, USA
| | - Thomas H. Meek
- Obesity Research, Novo Nordisk Research Center Seattle, Seattle, Washington, USA
- Discovery Technologies & Genomics, Novo Nordisk Research Centre Oxford, Oxford, United Kingdom
| | - Kevin L. Grove
- Obesity Research, Novo Nordisk Research Center Seattle, Seattle, Washington, USA
| | - Bao Anh N. Phan
- Department of Medicine, University of Washington Medicine Diabetes Institute, Seattle, Washington, USA
| | - Gregory J. Morton
- Department of Medicine, University of Washington Medicine Diabetes Institute, Seattle, Washington, USA
| | - Kevin W. Williams
- Department of Internal Medicine, Center for Hypothalamic Research, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA
| | - Michael W. Schwartz
- Department of Medicine, University of Washington Medicine Diabetes Institute, Seattle, Washington, USA
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The impact of caloric availability on eating behavior and ultra-processed food reward. Appetite 2022; 178:106274. [PMID: 35963586 DOI: 10.1016/j.appet.2022.106274] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 07/07/2022] [Accepted: 08/07/2022] [Indexed: 12/19/2022]
Abstract
The food environment has changed rapidly and dramatically in the last 50 years. While industrial food processing has increased the safety and stability of the food supply, a rapid expansion in the scope and scale of food processing in the 1980's has resulted in a market dominated by ultra-processed foods. Here, we use the NOVA definition of category 4 ultra-processed foods (UPFs) as they make up around 58% of total calories consumed in the US and 66% of calories in US children. UPFs are formulated from ingredients with no or infrequent culinary use, contain additives, and have a long shelf-life, spending long periods in contact with packaging materials, allowing for the absorption of compounds from those materials. The full implications of this dietary shift to UPFs on human health and disease outcomes are difficult, if not impossible, to quantify. However, UPF consumption is linked with various forms of cancer, increased cardiovascular disease, and increased all-cause mortality. Understanding food choice is, therefore, a critical problem in health research. Although many factors influence food choice, here we focus on the properties of the foods themselves. UPFs are generally treated as food, not as the highly refined, industrialized substances that they are, whose properties and components must be studied. Here, we examine one property of UPFs, that they deliver useable calories rapidly as a potential factor driving UPF overconsumption. First, we explore evidence that UPFs deliver calories more rapidly. Next, we examine the role of the gut-brain axis and its interplay with canonical reward systems, and last, we describe how speed affects both basic learning processes and drugs of abuse.
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Abstract
Despite decades of obesity research and various public health initiatives, obesity remains a major public health concern. Our most drastic but most effective treatment of obesity is bariatric surgery with weight loss and improvements in co-morbidities, including resolution of type 2 diabetes (T2D). However, the mechanisms by which surgery elicits metabolic benefits are still not well understood. One proposed mechanism is through signals generated by the intestine (nutrients, neuronal, and/or endocrine) that communicate nutrient status to the brain. In this review, we discuss the contributions of gut-brain communication to the physiological regulation of body weight and its impact on the success of bariatric surgery. Advancing our understanding of the mechanisms that drive bariatric surgery-induced metabolic benefits will ultimately lead to the identification of novel, less invasive strategies to treat obesity.
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Affiliation(s)
- Maigen Bethea
- Department of Pediatrics, Nutrition Section, University of Colorado Anschutz Medical Campus, 12801 E 17th Ave. Research Complex 1 South 7th Floor, Aurora, CO, 80045, USA
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, 12801 E 17th Ave. Research Complex 1 South 7th Floor, Aurora, CO, 80045, USA
| | - Darleen A Sandoval
- Department of Pediatrics, Nutrition Section, University of Colorado Anschutz Medical Campus, 12801 E 17th Ave. Research Complex 1 South 7th Floor, Aurora, CO, 80045, USA.
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, 12801 E 17th Ave. Research Complex 1 South 7th Floor, Aurora, CO, 80045, USA.
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Kolling LJ, Tatti R, Lowry T, Loeven AM, Fadool JM, Fadool DA. Modulating the Excitability of Olfactory Output Neurons Affects Whole-Body Metabolism. J Neurosci 2022; 42:5966-5990. [PMID: 35710623 PMCID: PMC9337614 DOI: 10.1523/jneurosci.0190-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 06/06/2022] [Accepted: 06/08/2022] [Indexed: 01/29/2023] Open
Abstract
Metabolic state can alter olfactory sensitivity, but it is unknown whether the activity of the olfactory bulb (OB) may fine tune metabolic homeostasis. Our objective was to use CRISPR gene editing in male and female mice to enhance the excitability of mitral/tufted projection neurons (M/TCs) of the OB to test for improved metabolic health. Ex vivo slice recordings of MCs in CRISPR mice confirmed increased excitability due the targeted loss of Kv1.3 channels, which resulted in a less negative resting membrane potential (RMP), enhanced action potential (AP) firing, and insensitivity to the selective channel blocker margatoxin (MgTx). CRISPR mice exhibited enhanced odor discrimination using a habituation/dishabituation paradigm. CRISPR mice were challenged for 25 weeks with a moderately high-fat (MHF) diet, and compared with littermate controls, male mice were resistance to diet-induced obesity (DIO). Female mice did not exhibit DIO. CRISPR male mice gained less body weight, accumulated less white adipose tissue, cleared a glucose challenge more quickly, and had less serum leptin and liver triglycerides. CRISPR male mice consumed equivalent calories as control littermates, and had unaltered energy expenditure (EE) and locomotor activity, but used more fats for metabolic substrate over that of carbohydrates. Counter to CRISPR-engineered mice, by using chemogenetics to decrease M/TC excitability in male mice, activation of inhibitory designer receptors exclusively activated by designer drugs (DREADDs) caused a decrease in odor discrimination, and resulted in a metabolic profile that was obesogenic, mice had reduced EE and oxygen consumption (VO2). We conclude that the activity of M/TC projection neurons canonically carries olfactory information and simultaneously can regulate whole-body metabolism.SIGNIFICANCE STATEMENT The olfactory system drives food choice, and olfactory sensitivity is strongly correlated to hunger and fullness. Olfactory function thereby influences nutritional balance and obesity outcomes. Obesity has become a health and financial crisis in America, shortening life expectancy and increasing the severity of associated illnesses. It is expected that 51% of Americans will be obese by the year 2030. Using CRISPR gene editing and chemogenetic approaches, we discovered that changing the excitability of output neurons in the olfactory bulb (OB) affects metabolism and body weight stabilization in mice. Our results suggest that long-term therapeutic targeting of OB activity to higher processing centers may be a future clinical treatment of obesity or type II Diabetes.
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Affiliation(s)
- Louis John Kolling
- Institute of Molecular Biophysics, The Florida State University, Tallahassee, Florida 32306
| | - Roberta Tatti
- Department of Biological Science, The Florida State University, Tallahassee, Florida 32306
| | - Troy Lowry
- Department of Biological Science, The Florida State University, Tallahassee, Florida 32306
| | - Ashley M Loeven
- Department of Biological Science, The Florida State University, Tallahassee, Florida 32306
| | - James M Fadool
- Department of Biological Science, The Florida State University, Tallahassee, Florida 32306
- Program in Neuroscience, The Florida State University, Tallahassee, Florida 32306
| | - Debra Ann Fadool
- Institute of Molecular Biophysics, The Florida State University, Tallahassee, Florida 32306
- Department of Biological Science, The Florida State University, Tallahassee, Florida 32306
- Program in Neuroscience, The Florida State University, Tallahassee, Florida 32306
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Chadwick SR, Güler AD. Local Drd1-neurons input to subgroups of arcuate AgRP/NPY-neurons. iScience 2022; 25:104605. [PMID: 35789850 PMCID: PMC9250019 DOI: 10.1016/j.isci.2022.104605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 05/02/2022] [Accepted: 06/08/2022] [Indexed: 11/21/2022] Open
Abstract
Obesity is a pandemic afflicting more than 300 million people worldwide, driven by consumption of calorically dense and highly rewarding foods. Dopamine (DA) signaling has been implicated in neural responses to highly palatable nutrients, but the exact mechanisms through which DA modulates homeostatic feeding circuits remains unknown. A subpopulation of arcuate (ARC) agouti-related peptide (AgRP)/neuropeptide Y (NPY) (ARCAgRP/NPY+) neurons express the D(1A) dopamine receptor (Drd1) and are stimulated by DA, suggesting one potential avenue for dopaminergic regulation of food intake. Using patch clamp electrophysiology, we evaluated the responses of ARC Drd1-expressing (ARCDrd1+) neurons to overnight fasting and leptin. Collectively, ARCDrd1+ neurons were less responsive to caloric deficit than ARCAgRP/NPY+ neurons; however, ARCDrd1+ neurons were inhibited by the satiety hormone leptin. Using Channelrhodopsin-2-Assisted Circuit Mapping, we identified novel subgroups of ARCDrd1+ neurons that inhibit or excite ARCAgRP/NPY+ neurons. These findings suggest dopamine receptive neurons have multimodal actions in food intake circuits.
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Affiliation(s)
- Sean R. Chadwick
- Program in Fundamental Neuroscience and the Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Ali D. Güler
- Program in Fundamental Neuroscience and the Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
- Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22903, USA
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Alcantara IC, Tapia APM, Aponte Y, Krashes MJ. Acts of appetite: neural circuits governing the appetitive, consummatory, and terminating phases of feeding. Nat Metab 2022; 4:836-847. [PMID: 35879462 PMCID: PMC10852214 DOI: 10.1038/s42255-022-00611-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 06/16/2022] [Indexed: 12/11/2022]
Abstract
The overconsumption of highly caloric and palatable foods has caused a surge in obesity rates in the past half century, thereby posing a healthcare challenge due to the array of comorbidities linked to heightened body fat accrual. Developing treatments to manage body weight requires a grasp of the neurobiological basis of appetite. In this Review, we discuss advances in neuroscience that have identified brain regions and neural circuits that coordinate distinct phases of eating: food procurement, food consumption, and meal termination. While pioneering work identified several hypothalamic nuclei to be involved in feeding, more recent studies have explored how neuronal populations beyond the hypothalamus, such as the mesolimbic pathway and nodes in the hindbrain, interconnect to modulate appetite. We also examine how long-term exposure to a calorically dense diet rewires feeding circuits and alters the response of motivational systems to food. Understanding how the nervous system regulates eating behaviour will bolster the development of medical strategies that will help individuals to maintain a healthy body weight.
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Affiliation(s)
- Ivan C Alcantara
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, USA
- Department of Neuroscience, Brown University, Providence, RI, USA
| | | | - Yeka Aponte
- National Institute on Drug Abuse (NIDA), National Institutes of Health, Baltimore, MD, USA.
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Michael J Krashes
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, USA.
- National Institute on Drug Abuse (NIDA), National Institutes of Health, Baltimore, MD, USA.
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Morales I. Brain regulation of hunger and motivation: The case for integrating homeostatic and hedonic concepts and its implications for obesity and addiction. Appetite 2022; 177:106146. [PMID: 35753443 DOI: 10.1016/j.appet.2022.106146] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 06/16/2022] [Accepted: 06/21/2022] [Indexed: 11/19/2022]
Abstract
Obesity and other eating disorders are marked by dysregulations to brain metabolic, hedonic, motivational, and sensory systems that control food intake. Classic approaches in hunger research have distinguished between hedonic and homeostatic processes, and have mostly treated these systems as independent. Hindbrain structures and a complex network of interconnected hypothalamic nuclei control metabolic processes, energy expenditure, and food intake while mesocorticolimbic structures are though to control hedonic and motivational processes associated with food reward. However, it is becoming increasingly clear that hedonic and homeostatic brain systems do not function in isolation, but rather interact as part of a larger network that regulates food intake. Incentive theories of motivation provide a useful route to explore these interactions. Adapting incentive theories of motivation can enable researchers to better how motivational systems dysfunction during disease. Obesity and addiction are associated with profound alterations to both hedonic and homeostatic brain systems that result in maladaptive patterns of consumption. A subset of individuals with obesity may experience pathological cravings for food due to incentive sensitization of brain systems that generate excessive 'wanting' to eat. Further progress in understanding how the brain regulates hunger and appetite may depend on merging traditional hedonic and homeostatic concepts of food reward and motivation.
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Affiliation(s)
- Ileana Morales
- Department of Psychology, University of Michigan, 530 Church Street, Ann Arbor, MI, 48109-1043, USA.
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