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Minaya DM, Kim JS, Kirkland R, Allen J, Cullinan S, Maclang N, de Lartigue G, de La Serre CB. Transfer with microbiota from lean donors prevents excessive weight gain and restores gut-brain vagal signaling in obese rats maintained on a high fat diet. RESEARCH SQUARE 2024:rs.3.rs-4438240. [PMID: 38853960 PMCID: PMC11160927 DOI: 10.21203/rs.3.rs-4438240/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Background The collection of microorganisms, mainly bacteria, which live in the gastrointestinal (GI) tract are collectible known as the gut microbiota. GI bacteria play an active role in regulation of the host's immune system and metabolism, as well as certain pathophysiological processes. Diet is the main factor modulating GI microbiota composition and recent studies have shown that high fat (HF) diets induce detrimental changes, known as dysbiosis, in the GI bacterial makeup. HF diet induced microbiota dysbiosis has been associated with structural and functional changes in gut-brain vagally mediated signaling system, associated with overeating and obesity. Although HF-driven changes in microbiota composition are sufficient to alter vagal signaling, it is unknown if restoring normal microbiota in obesity can improve gut-brain signaling and metabolic outcomes. In this study, we evaluated the effect of lean gut microbiota transfer in obese, vagally compromised, rats on gut-brain communication, food intake, and body weight. Male Sprague-Dawley rats were maintained on regular chow, or 45% HF diet for nine weeks followed by three weeks of microbiota depletion using an antibiotic cocktail. The animals were then divided into four groups (n=10 each): LF - control group on regular chow, LF-LF - chow fed animals that received antibiotics and microbiota from chow fed animals, HF-LF - HF fed animals that received microbiota from chow fed animals, and HF-HF - HF fed animals that received microbiota from HF fed animals. Animals were gavaged with donor microbiota for three consecutive days on week one and once a week thereafter for three more weeks. HF-LF animals received inulin as a prebiotic to aid the establishment of the lean microbiome. Results We found that transferring a LF microbiota to HF fed animals (HF-LF) reduced caloric intake during the light phase when compared with HF-HF rats and prevented additional excessive weight gain. We did not observe significant changes in the density of vagal afferents terminating in the brainstem among the groups, however, HF-LF animals displayed an increase in postprandial activation of both primary sensory neurons innervating the GI tract and brainstem secondary neurons. Conclusions We concluded from these data that normalizing microbiota composition in obese rats improves gut-brain communication and restores normal feeding patterns which was associated with a reduction in weight gain.
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Affiliation(s)
- Dulce M. Minaya
- Department of Nutritional Science, University of Georgia, Athens, GA
| | | | - Rebecca Kirkland
- Department of Nutritional Science, University of Georgia, Athens, GA
| | - Jillian Allen
- Department of Nutritional Science, University of Georgia, Athens, GA
| | - Sitara Cullinan
- Department of Nutritional Science, University of Georgia, Athens, GA
| | - Neil Maclang
- Department of Nutritional Science, University of Georgia, Athens, GA
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Wood CP, Alvarez C, DiPatrizio NV. Cholinergic Neurotransmission Controls Orexigenic Endocannabinoid Signaling in the Gut in Diet-Induced Obesity. J Neurosci 2024; 44:e0813232024. [PMID: 38594069 PMCID: PMC11097264 DOI: 10.1523/jneurosci.0813-23.2024] [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: 05/04/2023] [Revised: 03/12/2024] [Accepted: 03/30/2024] [Indexed: 04/11/2024] Open
Abstract
The brain bidirectionally communicates with the gut to control food intake and energy balance, which becomes dysregulated in obesity. For example, endocannabinoid (eCB) signaling in the small-intestinal (SI) epithelium is upregulated in diet-induced obese (DIO) mice and promotes overeating by a mechanism that includes inhibiting gut-brain satiation signaling. Upstream neural and molecular mechanism(s) involved in overproduction of orexigenic gut eCBs in DIO, however, are unknown. We tested the hypothesis that overactive parasympathetic signaling at the muscarinic acetylcholine receptors (mAChRs) in the SI increases biosynthesis of the eCB, 2-arachidonoyl-sn-glycerol (2-AG), which drives hyperphagia via local CB1Rs in DIO. Male mice were maintained on a high-fat/high-sucrose Western-style diet for 60 d, then administered several mAChR antagonists 30 min prior to tissue harvest or a food intake test. Levels of 2-AG and the activity of its metabolic enzymes in the SI were quantitated. DIO mice, when compared to those fed a low-fat/no-sucrose diet, displayed increased expression of cFos protein in the dorsal motor nucleus of the vagus, which suggests an increased activity of efferent cholinergic neurotransmission. These mice exhibited elevated levels of 2-AG biosynthesis in the SI, that was reduced to control levels by mAChR antagonists. Moreover, the peripherally restricted mAChR antagonist, methylhomatropine bromide, and the peripherally restricted CB1R antagonist, AM6545, reduced food intake in DIO mice for up to 24 h but had no effect in mice conditionally deficient in SI CB1Rs. These results suggest that hyperactivity at mAChRs in the periphery increases formation of 2-AG in the SI and activates local CB1Rs, which drives hyperphagia in DIO.
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Affiliation(s)
- Courtney P Wood
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, California 92521
- University of California Riverside Center for Cannabinoid Research, Riverside, California 92521
| | - Camila Alvarez
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, California 92521
- University of California Riverside Center for Cannabinoid Research, Riverside, California 92521
| | - Nicholas V DiPatrizio
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, California 92521
- University of California Riverside Center for Cannabinoid Research, Riverside, California 92521
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3
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Gruber T, Lechner F, Murat C, Contreras RE, Sanchez-Quant E, Miok V, Makris K, Le Thuc O, González-García I, García-Clave E, Althammer F, Krabichler Q, DeCamp LM, Jones RG, Lutter D, Williams RH, Pfluger PT, Müller TD, Woods SC, Pospisilik JA, Martinez-Jimenez CP, Tschöp MH, Grinevich V, García-Cáceres C. High-calorie diets uncouple hypothalamic oxytocin neurons from a gut-to-brain satiation pathway via κ-opioid signaling. Cell Rep 2023; 42:113305. [PMID: 37864798 PMCID: PMC10636643 DOI: 10.1016/j.celrep.2023.113305] [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: 08/04/2022] [Revised: 08/21/2023] [Accepted: 10/04/2023] [Indexed: 10/23/2023] Open
Abstract
Oxytocin-expressing paraventricular hypothalamic neurons (PVNOT neurons) integrate afferent signals from the gut, including cholecystokinin (CCK), to adjust whole-body energy homeostasis. However, the molecular underpinnings by which PVNOT neurons orchestrate gut-to-brain feeding control remain unclear. Here, we show that mice undergoing selective ablation of PVNOT neurons fail to reduce food intake in response to CCK and develop hyperphagic obesity on a chow diet. Notably, exposing wild-type mice to a high-fat/high-sugar (HFHS) diet recapitulates this insensitivity toward CCK, which is linked to diet-induced transcriptional and electrophysiological aberrations specifically in PVNOT neurons. Restoring OT pathways in diet-induced obese (DIO) mice via chemogenetics or polypharmacology sufficiently re-establishes CCK's anorexigenic effects. Last, by single-cell profiling, we identify a specialized PVNOT neuronal subpopulation with increased κ-opioid signaling under an HFHS diet, which restrains their CCK-evoked activation. In sum, we document a (patho)mechanism by which PVNOT signaling uncouples a gut-brain satiation pathway under obesogenic conditions.
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Affiliation(s)
- Tim Gruber
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany; Department of Metabolism and Nutritional Programming, Van Andel Institute, Grand Rapids, MI 49506, USA; Department of Epigenetics, Van Andel Institute, Grand Rapids, MI 49506, USA.
| | - Franziska Lechner
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Cahuê Murat
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Raian E Contreras
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Eva Sanchez-Quant
- Helmholtz Pioneer Campus (HPC), Helmholtz Zentrum München, Neuherberg, Germany
| | - Viktorian Miok
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Konstantinos Makris
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany; Computational Discovery Research, Institute for Diabetes and Obesity (IDO), Helmholtz Diabetes Center (HDC), Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Ophélia Le Thuc
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Ismael González-García
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Elena García-Clave
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | | | - Quirin Krabichler
- Department of Neuropeptide Research in Psychiatry, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Lisa M DeCamp
- Department of Metabolism and Nutritional Programming, Van Andel Institute, Grand Rapids, MI 49506, USA
| | - Russell G Jones
- Department of Metabolism and Nutritional Programming, Van Andel Institute, Grand Rapids, MI 49506, USA
| | - Dominik Lutter
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany; Computational Discovery Research, Institute for Diabetes and Obesity (IDO), Helmholtz Diabetes Center (HDC), Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Rhiannan H Williams
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute for Neurogenomics, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | - Paul T Pfluger
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany; Research Unit NeuroBiology of Diabetes, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Neurobiology of Diabetes, TUM School of Medicine, Technical University Munich, 80333 Munich, Germany
| | - Timo D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany; Department of Pharmacology and Experimental Therapy, Institute for Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls Hospitals and Clinics, Tübingen, Germany
| | - Stephen C Woods
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati, OH, USA
| | - John Andrew Pospisilik
- Department of Metabolism and Nutritional Programming, Van Andel Institute, Grand Rapids, MI 49506, USA; Department of Epigenetics, Van Andel Institute, Grand Rapids, MI 49506, USA
| | - Celia P Martinez-Jimenez
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI 49506, USA; TUM School of Medicine, Technical University of Munich, Munich, Germany
| | - Matthias H Tschöp
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany; Division of Metabolic Diseases, Department of Medicine, Technische Universität, Munich, Germany
| | - Valery Grinevich
- Department of Neuropeptide Research in Psychiatry, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany; Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, GA, USA.
| | - Cristina García-Cáceres
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany; Medizinische Klinik und Poliklinik IV, Klinikum der Universität, Ludwig-Maximilians-Universität München, 80336 Munich, Germany.
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Park SJ, Zides CG, Beyak MJ. Mechanical activation of vagal afferents involves opposing cation and TREK1 currents and NO regulation. Can J Physiol Pharmacol 2023; 101:521-528. [PMID: 37311256 DOI: 10.1139/cjpp-2022-0345] [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] [Indexed: 06/15/2023]
Abstract
Vagal afferents convey signals of mechanical stimulation in the gut to the brain, which is essential for the regulation of food intake. However, ion channels sensing mechanical stimuli are not fully understood. This study aimed to examine the ionic currents activated by mechanical stimulation and a possible neuro-modulatory role of nitric oxide on vagal afferents. Nodose neuronal currents and potentials, and intestinal afferent firing by mechanical stimulation were measured by whole-cell patch clamp, and in vitro afferent recording, respectively. Osmotically activated cation and two-pore domain K+ currents were identified in nodose neurons. The membrane potential displayed a biphasic change under hypotonic stimulation. Cation channel-mediated depolarization was followed by a hyperpolarization mediated by K+ channels. The latter was inhibited by l-methionine (TREK1 channel inhibitor) and l-NNA (nitric oxide synthase inhibitor). Correspondingly, mechanical stimulation activated opposing cation and TREK1 currents. NOS inhibition decreased TREK1 currents and potentiated jejunal afferent nerve firing induced by mechanical stimuli. This study suggested a novel activation mechanism of ion channels underlying adaptation under mechanical distension in vagal afferent neurons. The guts' ability to perceive mechanical stimuli is vital in determining how it responds to food intake. The mechanosensation through ion channels could initiate and control gut function.
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Affiliation(s)
- Sung Jin Park
- Gastrointestinal Disease Research Unit, Kingston General Hospital, Queen's University, Kingston, ON, K7L2V7, Canada
| | - Carter G Zides
- Gastrointestinal Disease Research Unit, Kingston General Hospital, Queen's University, Kingston, ON, K7L2V7, Canada
| | - Michael J Beyak
- Gastrointestinal Disease Research Unit, Kingston General Hospital, Queen's University, Kingston, ON, K7L2V7, Canada
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5
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Page AJ. Plasticity of gastrointestinal vagal afferents in terms of feeding-related physiology and pathophysiology. J Physiol 2023. [PMID: 37737742 DOI: 10.1113/jp284075] [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: 06/09/2023] [Accepted: 09/07/2023] [Indexed: 09/23/2023] Open
Abstract
Gastrointestinal vagal afferents play an important role in communicating food related information from the gut to the brain. This information initiates vago-vagal reflexes essential for gut functions, including gut motility and secretions. These afferents also play a role in energy homeostasis, signalling the arrival, amount and nutrient composition of a meal to the central nervous system where it is processed ultimately leading to termination of a meal. Vagal afferent responses to food related stimuli demonstrate a high degree of plasticity, responding to short term changes in nutritional demand, such as the fluctuations that occur across a 24-hr or in response to a fast, as well as long term changes in energy demand, such as occurs during pregnancy. This plasticity is disrupted in disease states, such as obesity or chronic stress where there is hypo- and hypersensitivity of these afferents, respectively. Improved understanding of the plasticity of these afferents will enable identification of new treatment options for diseases associated with vagal afferent function.
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Affiliation(s)
- Amanda J Page
- Vagal Afferent Research Group, School of Biomedicine, University of Adelaide, Adelaide, South Australia, Australia
- Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute, SAHMRI, Adelaide, South Australia, Australia
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Frick LD, Hankir MK, Borner T, Malagola E, File B, Gero D. Novel Insights into the Physiology of Nutrient Sensing and Gut-Brain Communication in Surgical and Experimental Obesity Therapy. Obes Surg 2023; 33:2906-2916. [PMID: 37474864 PMCID: PMC10435392 DOI: 10.1007/s11695-023-06739-4] [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: 05/10/2023] [Revised: 07/05/2023] [Accepted: 07/14/2023] [Indexed: 07/22/2023]
Abstract
Despite standardized surgical technique and peri-operative care, metabolic outcomes of bariatric surgery are not uniform. Adaptive changes in brain function may play a crucial role in achieving optimal postbariatric weight loss. This review follows the anatomic-physiologic structure of the postbariatric nutrient-gut-brain communication chain through its key stations and provides a concise summary of recent findings in bariatric physiology, with a special focus on the composition of the intestinal milieu, intestinal nutrient sensing, vagal nerve-mediated gastrointestinal satiation signals, circulating hormones and nutrients, as well as descending neural signals from the forebrain. The results of interventional studies using brain or vagal nerve stimulation to induce weight loss are also summarized. Ultimately, suggestions are made for future diagnostic and therapeutic research for the treatment of obesity.
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Affiliation(s)
- Lukas D Frick
- Institute of Neuropathology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Mohammed K Hankir
- Department of Experimental Surgery, University Hospital Würzburg, Würzburg, Germany
| | - Tito Borner
- Department of Biobehavioral Health Sciences, School of Nursing, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Ermanno Malagola
- Division of Digestive and Liver Diseases, Department of Medicine and Irving Cancer Research Center, Columbia University Medical Center, New York, NY, 10032, USA
| | - Bálint File
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary, Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Budapest, Hungary
- Wigner Research Centre for Physics, Budapest, Hungary
| | - Daniel Gero
- Department of Surgery and Transplantation, University Hospital Zurich, University of Zurich, Rämistrasse 100, 8091, Zürich, Switzerland.
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Brant BJA, Yu Y, Omar AA, Jaramillo Polanco JO, Lopez Lopez CD, Jiménez Vargas NN, Tsang Q, McDonell A, Takami K, Reed DE, Lomax AE, Vanner SJ, Tuck CJ. Dietary monosodium glutamate increases visceral hypersensitivity in a mouse model of visceral pain. Neurogastroenterol Motil 2023; 35:e14596. [PMID: 37248774 DOI: 10.1111/nmo.14596] [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: 07/07/2022] [Revised: 01/24/2023] [Accepted: 04/03/2023] [Indexed: 05/31/2023]
Abstract
BACKGROUND Monosodium glutamate (MSG) has been identified as a trigger of abdominal pain in irritable bowel syndrome (IBS), but the mechanism is unknown. This study examined whether MSG causes visceral hypersensitivity using a water-avoidance stress (WAS) mouse model of visceral pain. METHODS Mice were divided into four groups receiving treatment for 6 days: WAS + MSG gavage, WAS + saline gavage, sham-WAS + MSG gavage, and sham-WAS + saline gavage. The acute effects of intraluminal administration of 10 μM MSG on jejunal extrinsic afferent nerve sensitivity to distension (0-60 mmHg) were examined using ex vivo extracellular recordings. MSG was also applied directly to jejunal afferents from untreated mice. Glutamate concentration was measured in serum, and in the serosal compartment of Ussing chambers following apical administration. KEY RESULTS Acute intraluminal MSG application increased distension responses of jejunal afferent nerves from mice exposed to WAS + MSG. This effect was mediated by wide dynamic range and high-threshold units at both physiologic and noxious pressures (10-60 mmHg, p < 0.05). No effect of MSG was observed in the other groups, or when applied directly to the jejunal afferent nerves. Serum glutamate was increased in mice exposed to WAS + MSG compared to sham-WAS + saline, and serosal glutamate increased using WAS tissue (p = 0.0433). CONCLUSIONS AND INFERENCES These findings demonstrate that repeated exposure to MSG in mice leads to sensitization of jejunal afferent nerves to acute ex vivo exposure to MSG. This may contribute to visceral hypersensitivity reported in response to MSG in patients with IBS.
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Affiliation(s)
- Bailey J A Brant
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Yang Yu
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Amal Abu Omar
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | | | - Cintya D Lopez Lopez
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | | | - Quentin Tsang
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Abby McDonell
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Kaede Takami
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - David E Reed
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Alan E Lomax
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Stephen J Vanner
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Caroline J Tuck
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
- Department of Dietetics, Nutrition and Sport, La Trobe University, Melbourne, Victoria, Australia
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Weninger SN, Herman C, Meyer RK, Beauchemin ET, Kangath A, Lane AI, Martinez TM, Hasneen T, Jaramillo SA, Lindsey J, Vedantam G, Cai H, Cope EK, Caporaso JG, Duca FA. Oligofructose improves small intestinal lipid-sensing mechanisms via alterations to the small intestinal microbiota. MICROBIOME 2023; 11:169. [PMID: 37533066 PMCID: PMC10394784 DOI: 10.1186/s40168-023-01590-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 06/02/2023] [Indexed: 08/04/2023]
Abstract
BACKGROUND Upper small intestinal dietary lipids activate a gut-brain axis regulating energy homeostasis. The prebiotic, oligofructose (OFS) improves body weight and adiposity during metabolic dysregulation but the exact mechanisms remain unknown. This study examines whether alterations to the small intestinal microbiota following OFS treatment improve small intestinal lipid-sensing to regulate food intake in high fat (HF)-fed rats. RESULTS In rats fed a HF diet for 4 weeks, OFS supplementation decreased food intake and meal size within 2 days, and reduced body weight and adiposity after 6 weeks. Acute (3 day) OFS treatment restored small intestinal lipid-induced satiation during HF-feeding, and was associated with increased small intestinal CD36 expression, portal GLP-1 levels and hindbrain neuronal activation following a small intestinal lipid infusion. Transplant of the small intestinal microbiota from acute OFS treated donors into HF-fed rats also restored lipid-sensing mechanisms to lower food intake. 16S rRNA gene sequencing revealed that both long and short-term OFS altered the small intestinal microbiota, increasing Bifidobacterium relative abundance. Small intestinal administration of Bifidobacterium pseudolongum to HF-fed rats improved small intestinal lipid-sensing to decrease food intake. CONCLUSION OFS supplementation rapidly modulates the small intestinal gut microbiota, which mediates improvements in small intestinal lipid sensing mechanisms that control food intake to improve energy homeostasis. Video Abstract.
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Affiliation(s)
| | - Chloe Herman
- Center for Applied Microbiome Science, Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
| | - Rachel K Meyer
- Department of Nutritional Sciences, University of Arizona, Tucson, USA
| | - Eve T Beauchemin
- School of Animal and Comparative Biomedical Sciences, College of Agricultural and Life Sciences, University of Arizona, Tucson, USA
- Faculty of Medicine, Department of Microbiology & Immunology, McGill University, Montreal, QC, Canada
| | - Archana Kangath
- School of Animal and Comparative Biomedical Sciences, College of Agricultural and Life Sciences, University of Arizona, Tucson, USA
| | - Adelina I Lane
- Department of Physiology, University of Arizona, Tucson, USA
| | | | - Tahia Hasneen
- Department of Neuroscience, University of Arizona, Tucson, AZ, USA
| | - Sierra A Jaramillo
- Center for Applied Microbiome Science, Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
| | - Jason Lindsey
- School of Animal and Comparative Biomedical Sciences, College of Agricultural and Life Sciences, University of Arizona, Tucson, USA
| | - Gayatri Vedantam
- School of Animal and Comparative Biomedical Sciences, College of Agricultural and Life Sciences, University of Arizona, Tucson, USA
- Department of Immunobiology, University of Arizona, Tucson, AZ, USA
- BIO5 Institute for Collaborative Research, University of Arizona, Tucson, USA
| | - Haijiang Cai
- Department of Neuroscience, University of Arizona, Tucson, AZ, USA
- BIO5 Institute for Collaborative Research, University of Arizona, Tucson, USA
| | - Emily K Cope
- Center for Applied Microbiome Science, Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - J Gregory Caporaso
- Center for Applied Microbiome Science, Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Frank A Duca
- School of Animal and Comparative Biomedical Sciences, College of Agricultural and Life Sciences, University of Arizona, Tucson, USA.
- BIO5 Institute for Collaborative Research, University of Arizona, Tucson, USA.
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Girardi G, Zumpano D, Goshi N, Raybould H, Seker E. Cultured Vagal Afferent Neurons as Sensors for Intestinal Effector Molecules. BIOSENSORS 2023; 13:601. [PMID: 37366967 DOI: 10.3390/bios13060601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 05/23/2023] [Accepted: 05/24/2023] [Indexed: 06/28/2023]
Abstract
The gut-brain axis embodies the bi-directional communication between the gastrointestinal tract and the central nervous system (CNS), where vagal afferent neurons (VANs) serve as sensors for a variety of gut-derived signals. The gut is colonized by a large and diverse population of microorganisms that communicate via small (effector) molecules, which also act on the VAN terminals situated in the gut viscera and consequently influence many CNS processes. However, the convoluted in vivo environment makes it difficult to study the causative impact of the effector molecules on VAN activation or desensitization. Here, we report on a VAN culture and its proof-of-principle demonstration as a cell-based sensor to monitor the influence of gastrointestinal effector molecules on neuronal behavior. We initially compared the effect of surface coatings (poly-L-lysine vs. Matrigel) and culture media composition (serum vs. growth factor supplement) on neurite growth as a surrogate of VAN regeneration following tissue harvesting, where the Matrigel coating, but not the media composition, played a significant role in the increased neurite growth. We then used both live-cell calcium imaging and extracellular electrophysiological recordings to show that the VANs responded to classical effector molecules of endogenous and exogenous origin (cholecystokinin serotonin and capsaicin) in a complex fashion. We expect this study to enable platforms for screening various effector molecules and their influence on VAN activity, assessed by their information-rich electrophysiological fingerprints.
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Affiliation(s)
- Gregory Girardi
- Department of Biomedical Engineering, University of California-Davis, Davis, CA 95616, USA
| | - Danielle Zumpano
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616, USA
| | - Noah Goshi
- Department of Biomedical Engineering, University of California-Davis, Davis, CA 95616, USA
| | - Helen Raybould
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616, USA
| | - Erkin Seker
- Department of Electrical and Computer Engineering, University of California-Davis, Davis, CA 95616, USA
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10
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Wunderlich ALM, Martins AB, de Souza CF, Stopa LRS, Monteiro ÉCAM, Aguiar DD, Guergolette RP, Zaia CTBV, Uchôa ET. Neonatal overnutrition, but not neonatal undernutrition, disrupts CCK-induced hypophagia and neuron activation of the nucleus of the solitary tract and paraventricular nucleus of hypothalamus of male Wistar rats. Brain Res Bull 2023; 195:109-119. [PMID: 36813046 DOI: 10.1016/j.brainresbull.2023.02.012] [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: 09/12/2022] [Revised: 02/16/2023] [Accepted: 02/18/2023] [Indexed: 02/22/2023]
Abstract
Metabolic programming may be induced by reduction or enhancement of litter size, which lead to neonatal over or undernutrition, respectively. Changes in neonatal nutrition can challenge some regulatory processes in adulthood, such as the hypophagic effect of cholecystokinin (CCK). In order to investigate the effects of nutritional programming on the anorexigenic function of CCK in adulthood, pups were raised in small (SL, 3 pups per dam), normal (NL, 10 pups per dam), or large litters (LL, 16 pups per dam), and on postnatal day 60, male rats were treated with vehicle or CCK (10 µg/Kg) for the evaluation of food intake and c-Fos expression in the area postrema (AP), nucleus of solitary tract (NTS), and paraventricular (PVN), arcuate (ARC), ventromedial (VMH), and dorsomedial (DMH) nuclei of the hypothalamus. Overnourished rats showed increased body weight gain that was inversely correlated with neuronal activation of PaPo, VMH, and DMH neurons, whereas undernourished rats had lower body weight gain, inversely correlated with increased neuronal activation of PaPo only. SL rats showed no anorexigenic response and lower neuron activation in the NTS and PVN induced by CCK. LL exhibited preserved hypophagia and neuron activation in the AP, NTS, and PVN in response to CCK. CCK showed no effect in c-Fos immunoreactivity in the ARC, VMH, and DMH in any litter. These results indicate that anorexigenic actions, associated with neuron activation in the NTS and PVN, induced by CCK were impaired by neonatal overnutrition. However, these responses were not disrupted by neonatal undernutrition. Thus, data suggest that an excess or poor supply of nutrients during lactation display divergent effects on programming CCK satiation signaling in male adult rats.
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Affiliation(s)
| | - Andressa Busetti Martins
- Multicenter Postgraduate Program in Physiological Sciences, State University of Londrina, Londrina, PR, Brazil
| | - Camila Franciele de Souza
- Multicenter Postgraduate Program in Physiological Sciences, State University of Londrina, Londrina, PR, Brazil
| | - Larissa Rugila S Stopa
- Postgraduate Program in Physiological Sciences, State University of Londrina, Londrina, PR, Brazil
| | | | - Danielly D Aguiar
- Postgraduate Program in Physiological Sciences, State University of Londrina, Londrina, PR, Brazil
| | - Rhauany P Guergolette
- Postgraduate Program in Physiological Sciences, State University of Londrina, Londrina, PR, Brazil
| | - Cássia Thaïs B V Zaia
- Postgraduate Program in Physiological Sciences, State University of Londrina, Londrina, PR, Brazil; Multicenter Postgraduate Program in Physiological Sciences, State University of Londrina, Londrina, PR, Brazil; Department of Physiological Sciences, State University of Londrina, Londrina, PR, Brazil
| | - Ernane Torres Uchôa
- Postgraduate Program in Physiological Sciences, State University of Londrina, Londrina, PR, Brazil; Multicenter Postgraduate Program in Physiological Sciences, State University of Londrina, Londrina, PR, Brazil; Department of Physiological Sciences, State University of Londrina, Londrina, PR, Brazil.
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11
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Clyburn C, Carson KE, Smith CR, Travagli RA, Browning KN. Brainstem astrocytes control homeostatic regulation of caloric intake. J Physiol 2023; 601:801-829. [PMID: 36696965 PMCID: PMC10026361 DOI: 10.1113/jp283566] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 12/08/2022] [Indexed: 01/27/2023] Open
Abstract
Prolonged high-fat diet (HFD) exposure is associated with hyperphagia, excess caloric intake and weight gain. After initial exposure to a HFD, a brief (24-48 h) period of hyperphagia is followed by the regulation of caloric intake and restoration of energy balance within an acute (3-5 day) period. Previous studies have demonstrated this occurs via a vagally mediated signalling cascade that increases glutamatergic transmission via activation of NMDA receptors located on gastric-projecting neurons of the dorsal motor nucleus of the vagus (DMV). The present study used electrophysiological recordings from thin brainstem slice preparations, in vivo recordings of gastric motility and tone, measurement of gastric emptying rates, and food intake studies to investigate the hypothesis that activation of brainstem astrocytes in response to acute HFD exposure is responsible for the increased glutamatergic drive to DMV neurons and the restoration of caloric balance. Pharmacological and chemogenetic inhibition of brainstem astrocytes reduced glutamatergic signalling and DMV excitability, dysregulated gastric tone and motility, attenuated the homeostatic delay in gastric emptying, and prevented the decrease in food intake that is observed during the period of energy regulation following initial exposure to HFD. Understanding the mechanisms involved in caloric regulation may provide critical insights into energy balance as well as into the hyperphagia that develops as these mechanisms are overcome. KEY POINTS: Initial exposure to a high fat diet is associated with a brief period of hyperphagia before caloric intake and energy balance is restored. This period of homeostatic regulation is associated with a vagally mediated signalling cascade that increases glutamatergic transmission to dorsal motor nucleus of the vagus (DMV) neurons via activation of synaptic NMDA receptors. The present study demonstrates that pharmacological and chemogenetic inhibition of brainstem astrocytes reduced glutamatergic signalling and DMV neuronal excitability, dysregulated gastric motility and tone and emptying, and prevented the regulation of food intake following high-fat diet exposure. Astrocyte regulation of glutamatergic transmission to DMV neurons appears to involve release of the gliotransmitters glutamate and ATP. Understanding the mechanisms involved in caloric regulation may provide critical insights into energy balance as well as into the hyperphagia that develops as these mechanisms are overcome.
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Affiliation(s)
- Courtney Clyburn
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, Hershey, PA
- Current position: Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR, 97056
| | - Kaitlin E. Carson
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, Hershey, PA
| | - Caleb R. Smith
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, Hershey, PA
| | - R. Alberto Travagli
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, Hershey, PA
- Current position: Neurobiology Research, Newport, NC 28570
| | - Kirsteen N. Browning
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, Hershey, PA
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12
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Tuck CJ, Abu Omar A, De Palma G, Osman S, Jiménez-Vargas NN, Yu Y, Bennet SM, Lopez-Lopez C, Jaramillo-Polanco JO, Baker CC, Bennett AS, Guzman-Rodriguez M, Tsang Q, Alward T, Rolland S, Morissette C, Verdu EF, Bercik P, Vanner SJ, Lomax AE, Reed DE. Changes in signalling from faecal neuroactive metabolites following dietary modulation of IBS pain. Gut 2022; 72:gutjnl-2022-327260. [PMID: 36591617 DOI: 10.1136/gutjnl-2022-327260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 11/23/2022] [Indexed: 01/03/2023]
Abstract
OBJECTIVE Dietary therapies for irritable bowel syndrome (IBS) have received increasing interest but predicting which patients will benefit remains a challenge due to a lack of mechanistic insight. We recently found evidence of a role for the microbiota in dietary modulation of pain signalling in a humanised mouse model of IBS. This randomised cross-over study aimed to test the hypothesis that pain relief following reduced consumption of fermentable carbohydrates is the result of changes in luminal neuroactive metabolites. DESIGN IBS (Rome IV) participants underwent four trial periods: two non-intervention periods, followed by a diet low (LFD) and high in fermentable carbohydrates for 3 weeks each. At the end of each period, participants completed questionnaires and provided stool. The effects of faecal supernatants (FS) collected before (IBS FS) and after a LFD (LFD FS) on nociceptive afferent neurons were assessed in mice using patch-clamp and ex vivo colonic afferent nerve recording techniques. RESULTS Total IBS symptom severity score and abdominal pain were reduced by the LFD (N=25; p<0.01). Excitability of neurons was increased in response to IBS FS, but this effect was reduced (p<0.01) with LFD FS from pain-responders. IBS FS from pain-responders increased mechanosensitivity of nociceptive afferent nerve axons (p<0.001), an effect lost following LFD FS administration (p=NS) or when IBS FS was administered in the presence of antagonists of histamine receptors or protease inhibitors. CONCLUSIONS In a subset of IBS patients with improvement in abdominal pain following a LFD, there is a decrease in pronociceptive signalling from FS, suggesting that changes in luminal mediators may contribute to symptom response.
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Affiliation(s)
- Caroline J Tuck
- Department of Sport, Exercise and Nutrition Sciences, La Trobe University, Melbourne, Victoria, Australia
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Amal Abu Omar
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
- Department of Physiology, Jordan University of Science and Technology, Irbid, Jordan
| | - Giada De Palma
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Samira Osman
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | | | - Yang Yu
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Sean Mp Bennet
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Cintya Lopez-Lopez
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | | | - Corey C Baker
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Aidan Sw Bennett
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | | | - Quentin Tsang
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Taylor Alward
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Sebastien Rolland
- Department of Medicine, Hopital Maisonneuve-Rosemont, Montreal, Québec, Canada
| | - Celine Morissette
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Elena F Verdu
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Premysl Bercik
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Stephen J Vanner
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Alan E Lomax
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - David E Reed
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
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13
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Huang X, Wang YJ, Xiang Y. Bidirectional communication between brain and visceral white adipose tissue: Its potential impact on Alzheimer's disease. EBioMedicine 2022; 84:104263. [PMID: 36122553 PMCID: PMC9490488 DOI: 10.1016/j.ebiom.2022.104263] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 08/21/2022] [Accepted: 08/24/2022] [Indexed: 11/20/2022] Open
Abstract
A variety of axes between brain and abdominal organs have been reported, but the interaction between brain and visceral white adipose tissue (vWAT) remains unclear. In this review, we summarized human studies on the association between brain and vWAT, and generalized their interaction and the underlying mechanisms according to animal and cell experiments. On that basis, we come up with the concept of the brain-vWAT axis (BVA). Furthermore, we analyzed the potential mechanisms of involvement of BVA in the pathogenesis of Alzheimer's disease (AD), including vWAT-derived fatty acids, immunological properties of vWAT, vWAT-derived retinoic acid and vWAT-regulated insulin resistance. The proposal of BVA may expand our understanding to some extent of how the vWAT impacts on brain health and diseases, and provide a novel approach to study the pathogenesis and treatment strategies of neurodegenerative disorders.
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14
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Valdez-Morales EE, Sánchez-Navarro CA, Reyes-Pavón D, Barrios-Garcia T, Ochoa-Cortes F, Barajas-Espinosa A, Barragán-Iglesias P, Guerrero-Alba R. TNF-α enhances sensory DRG neuron excitability through modulation of P2X3 receptors in an acute colitis model. Front Immunol 2022; 13:872760. [PMID: 36032155 PMCID: PMC9416886 DOI: 10.3389/fimmu.2022.872760] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 07/18/2022] [Indexed: 11/15/2022] Open
Abstract
Previous studies have demonstrated that acute colonic inflammation leads to an increase in dorsal root ganglia (DRG) neuronal excitability. However, the signaling elements implicated in this hyperexcitability have yet to be fully unraveled. Extracellular adenosine 5’-triphosphate (ATP) is a well-recognized sensory signaling molecule that enhances the nociceptive response after inflammation through activation of P2X3 receptors, which are expressed mainly by peripheral sensory neurons. The aim of this study is to continue investigating how P2X3 affects neuronal hypersensitivity in an acute colitis animal model. To achieve this, DNBS (Dinitrobenzene sulfonic acid; 200 mg/kg) was intrarectally administered to C57BL/6 mice, and inflammation severity was assessed according to the following parameters: weight loss, macroscopic and microscopic scores. Perforated patch clamp technique was used to evaluate neuronal excitability via measuring changes in rheobase and action potential firing in T8-L1 DRG neurons. A-317491, a well-established potent and selective P2X3 receptor antagonist, served to dissect their contribution to recorded responses. Protein expression of P2X3 receptors in DRG was evaluated by western blotting and immunofluorescence. Four days post-DNBS administration, colons were processed for histological analyses of ulceration, crypt morphology, goblet cell density, and immune cell infiltration. DRG neurons from DNBS-treated mice were significantly more excitable compared with controls; these changes correlated with increased P2X3 receptor expression. Furthermore, TNF-α mRNA expression was also significantly higher in inflamed colons compared to controls. Incubation of control DRG neurons with TNF-α resulted in similar cell hyperexcitability as measured in DNBS-derived neurons. The selective P2X3 receptor antagonist, A-317491, blocked the TNF-α-induced effect. These results support the hypothesis that TNF-α enhances colon-innervating DRG neuron excitability via modulation of P2X3 receptor activity.
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Affiliation(s)
| | - Carlos A. Sánchez-Navarro
- Departamento de Medicina, Centro de Ciencias de la Salud , Universidad Autónoma de Aguascalientes, Aguascalientes, Mexico
| | - Diana Reyes-Pavón
- Departamento de Fisiología y Farmacología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Aguascalientes, Mexico
| | - Tonatiuh Barrios-Garcia
- Departamento de Fisiología y Farmacología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Aguascalientes, Mexico
| | - Fernando Ochoa-Cortes
- Licenciatura en Enfermería, Escuela Superior de Huejutla, Universidad Autónoma del Estado de Hidalgo, Hidalgo, Mexico
| | - Alma Barajas-Espinosa
- Licenciatura en Enfermería, Escuela Superior de Huejutla, Universidad Autónoma del Estado de Hidalgo, Hidalgo, Mexico
| | - Paulino Barragán-Iglesias
- Departamento de Fisiología y Farmacología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Aguascalientes, Mexico
| | - Raquel Guerrero-Alba
- Departamento de Fisiología y Farmacología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Aguascalientes, Mexico
- *Correspondence: Raquel Guerrero-Alba,
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15
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Peiris M, Aktar R, Reed D, Cibert-Goton V, Zdanaviciene A, Halder W, Robinow A, Corke S, Dogra H, Knowles CH, Blackshaw A. Decoy bypass for appetite suppression in obese adults: role of synergistic nutrient sensing receptors GPR84 and FFAR4 on colonic endocrine cells. Gut 2022; 71:928-937. [PMID: 34083384 PMCID: PMC8995825 DOI: 10.1136/gutjnl-2020-323219] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 05/09/2021] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Colonic enteroendocrine cells (EECs) store and release potent anorectic hormones that are key regulators of satiety. EECs express multiple nutrient sensing receptors, particularly for medium-chain fatty acids (MCFAs): GPR84 and FFAR4. Here we show a non-surgical approach with targeted colonic delivery of MCFA, which induces EEC and neuronal activation leading to anorectic effects. DESIGN A randomised, double-blind, placebo-controlled, cross-over study was performed in obese adults given combined GPR84 and FFAR4 agonists in colonic release capsules before meals. We measured serum hormones, energy intake and appetite perception. Cell type, activation by agonists and hormone/serotonin release were determined in human colonic explants. Mouse colonic afferent nerve responses to nutrients/mediators were recorded electrophysiologically. RESULTS Subjects receiving GPR84 and FFAR4 agonists had reduced overall calorific intake and increased postprandial levels of PYY versus placebo. Receptors including GPR84 and FFAR4 were coexpressed on human colonic EEC. Activation of GPR84 exclusively induced intracellular pERK, whereas FFAR4 selectively activated pCaMKII. Coactivation of GPR84 and FFAR4 induced both phosphoproteins, and superadditive release of GLP-1 and PYY. Nutrients and hormones convergently activated murine colonic afterent nerves via GLP-1, Y2 and 5-HT3 receptors. CONCLUSIONS Colonic GPR84 and FFAR4 agonists reduce energy intake and increase postprandial PYY in obese adults. Human colonic EECs coexpress these receptors, which activate cells via parallel intracellular pathways and synergistically evoke hormone release. Further synergism occurs in sensory nerve responses to MCFA and EEC mediators. Thus, synergistic activation of colonic endocrine cells via nutrient receptors is an important target for metabolic regulation. TRAIL REGISTRATION NUMBER NCT04292236.
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Affiliation(s)
- Madusha Peiris
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Rubina Aktar
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - David Reed
- Gastrointestinal Diseases Research, Queen's University, Kingston, Queensland, Canada
| | - Vincent Cibert-Goton
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Ausra Zdanaviciene
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Writaja Halder
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Adam Robinow
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Simon Corke
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Harween Dogra
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Charles H Knowles
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Ashley Blackshaw
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
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16
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Wachsmuth HR, Weninger SN, Duca FA. Role of the gut-brain axis in energy and glucose metabolism. Exp Mol Med 2022; 54:377-392. [PMID: 35474341 PMCID: PMC9076644 DOI: 10.1038/s12276-021-00677-w] [Citation(s) in RCA: 67] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 07/01/2021] [Accepted: 07/08/2021] [Indexed: 12/12/2022] Open
Abstract
The gastrointestinal tract plays a role in the development and treatment of metabolic diseases. During a meal, the gut provides crucial information to the brain regarding incoming nutrients to allow proper maintenance of energy and glucose homeostasis. This gut-brain communication is regulated by various peptides or hormones that are secreted from the gut in response to nutrients; these signaling molecules can enter the circulation and act directly on the brain, or they can act indirectly via paracrine action on local vagal and spinal afferent neurons that innervate the gut. In addition, the enteric nervous system can act as a relay from the gut to the brain. The current review will outline the different gut-brain signaling mechanisms that contribute to metabolic homeostasis, highlighting the recent advances in understanding these complex hormonal and neural pathways. Furthermore, the impact of the gut microbiota on various components of the gut-brain axis that regulates energy and glucose homeostasis will be discussed. A better understanding of the gut-brain axis and its complex relationship with the gut microbiome is crucial for the development of successful pharmacological therapies to combat obesity and diabetes.
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Affiliation(s)
| | | | - Frank A Duca
- School of Animal and Comparative Biomedical Sciences, College of Agricultural and Life Sciences, University of Arizona, Tucson, AZ, USA. .,BIO5, University of Arizona, Tucson, AZ, USA.
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17
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The Isolated Mouse Jejunal Afferent Nerve Assay as a Tool to Assess the Effect of Botulinum Neurotoxins in Visceral Nociception. Toxins (Basel) 2022; 14:toxins14030205. [PMID: 35324702 PMCID: PMC8953691 DOI: 10.3390/toxins14030205] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 03/04/2022] [Accepted: 03/08/2022] [Indexed: 12/10/2022] Open
Abstract
For the past two decades, botulinum neurotoxin A (BoNT/A) has been described as a strong candidate in the treatment of pain. With the production of modified toxins and the potential new applications at the visceral level, there is a real need for tools allowing the assessment of these compounds. In this study, we evaluated the jejunal mesenteric afferent nerve assay to investigate BoNT/A effects on visceral nociception. This ex vivo model allowed the continuous recording of neuronal activity in response to various stimuli. BoNT/A was applied intraluminally during three successive distensions, and the jejunum was distended every 15 min for 3 h. Finally, samples were exposed to external capsaicin. BoNT/A intoxication was validated at the molecular level with the presence of cleaved synaptosomal-associated protein of 25 (SNAP25) in nerve terminals in the mucosa and musculosa layers 3 h after treatment. BoNT/A had a progressive inhibitory effect on multiunit discharge frequency induced by jejunal distension, with a significant decrease from 1 h after application without change in jejunal compliance. The capsaicin-induced discharge was also affected by the toxin. This assay allowed the description of an inhibitory effect of BoNT/A on afferent nerve activity in response to distension and capsaicin, suggesting BoNT/A could alleviate visceral nociception.
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18
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Mechanisms of reduced leptin-mediated satiety signaling during obesity. Int J Obes (Lond) 2022; 46:1212-1221. [PMID: 35241786 DOI: 10.1038/s41366-022-01079-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 11/17/2021] [Accepted: 01/17/2022] [Indexed: 11/08/2022]
Abstract
BACKGROUND/OBJECTIVES Disrupted leptin signaling in vagal afferent neurons contributes to hyperphagia and obesity. Thus, we tested the hypothesis that intrinsic negative regulators of leptin signaling, suppressor of cytokine signaling 3 (SOCS3) and protein tyrosine phosphatase 1B (PTP1B) underlie dysfunctional leptin-mediated vagal afferent satiety signaling during obesity. METHODS Experiments were performed on standard chow-fed control mice, high-fat fed (HFF), or low-fat fed (LFF) mice. SOCS3 and PTP1B expression were quantified using western blot and quantitative PCR. Nodose ganglion neuronal excitability and jejunal afferent sensitivity were measured by patch clamp and extracellular afferent recordings, respectively. RESULTS Increased expression of SOCS3 and PTP1B were observed in the jejunum of HFF mice. Prolonged incubation with leptin attenuated nodose ganglion neuronal excitability, and this effect was reversed by inhibition of SOCS3. Leptin potentiated jejunal afferent nerve responses to CCK in LFF mice but decreased them in HFF mice. Inhibition of SOCS3 restored impaired vagal afferent neuronal excitability and afferent nerve responses to satiety mediators during obesity. Two-pore domain K+ channel (K2P) conductance and nitric oxide (NO) production that we previously demonstrated were elevated during obesity were decreased by inhibitions of SOCS3 or PTP1B. CONCLUSIONS This study suggests that obesity impairs vagal afferent sensitivity via SOCS3 and PTP1B, likely as a consequence of obesity-induced hyperleptinemia. The mechanisms underlying leptin resistance appear also to cause a more global impairment of satiety-related vagal afferent responsiveness.
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Rodrigues VST, Moura EG, Peixoto TC, Soares P, Lopes BP, Bertasso IM, Silva BS, Cabral S, Kluck GEG, Atella GC, Trindade PL, Daleprane JB, Oliveira E, Lisboa PC. The model of litter size reduction induces long-term disruption of the gut-brain axis: An explanation for the hyperphagia of Wistar rats of both sexes. Physiol Rep 2022; 10:e15191. [PMID: 35146951 PMCID: PMC8831958 DOI: 10.14814/phy2.15191] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 12/10/2021] [Accepted: 01/04/2022] [Indexed: 04/26/2023] Open
Abstract
The gut microbiota affects the host's metabolic phenotype, impacting health and disease. The gut-brain axis unites the intestine with the centers of hunger and satiety, affecting the eating behavior. Deregulation of this axis can lead to obesity onset. Litter size reduction is a well-studied model for infant obesity because it causes overnutrition and programs for obesity. We hypothesize that animals raised in small litters (SL) have altered circuitry between the intestine and brain, causing hyperphagia. We investigated vagus nerve activity, the expression of c-Fos, brain-derived neurotrophic factor (BDNF), gastrointestinal (GI) hormone receptors, and content of bacterial phyla and short-chain fatty acids (SCFAs) in the feces of adult male and female Wistar rats overfed during lactation. On the 3rd day after birth, litter size was reduced to 3 pups/litter (SL males or SL females) until weaning. Controls had normal litter size (10 pups/litter: 5 males and 5 females). The rats were killed at 5 months of age. The male and female offspring were analyzed separately. The SL group of both sexes showed higher food consumption and body adiposity than the respective controls. SL animals presented dysbiosis (increased Firmicutes, decreased Bacteroidetes) and had increased vagus nerve activity. Only the SL males had decreased hypothalamic GLP-1 receptor expression, while only the SL females had lower acetate and propionate in the feces and higher CCK receptor expression in the hypothalamus. Thus, overfeeding during lactation differentially changes the gut-brain axis, contributing to hyperphagia of the offspring of both sexes.
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Affiliation(s)
- Vanessa S. T. Rodrigues
- Laboratory of Endocrine PhysiologyBiology InstituteState University of Rio de JaneiroRio de JaneiroBrazil
| | - Egberto G. Moura
- Laboratory of Endocrine PhysiologyBiology InstituteState University of Rio de JaneiroRio de JaneiroBrazil
| | - Thamara C. Peixoto
- Laboratory of Endocrine PhysiologyBiology InstituteState University of Rio de JaneiroRio de JaneiroBrazil
| | - Patricia N. Soares
- Laboratory of Endocrine PhysiologyBiology InstituteState University of Rio de JaneiroRio de JaneiroBrazil
| | - Bruna P. Lopes
- Laboratory of Endocrine PhysiologyBiology InstituteState University of Rio de JaneiroRio de JaneiroBrazil
| | - Iala M. Bertasso
- Laboratory of Endocrine PhysiologyBiology InstituteState University of Rio de JaneiroRio de JaneiroBrazil
| | - Beatriz S. Silva
- Laboratory of Endocrine PhysiologyBiology InstituteState University of Rio de JaneiroRio de JaneiroBrazil
| | - S. S. Cabral
- Laboratory of Lipids and Lipoprotein BiochemistryBiochemistry InstituteFederal University of Rio de JaneiroRio de JaneiroBrazil
| | - G. E. G. Kluck
- Laboratory of Lipids and Lipoprotein BiochemistryBiochemistry InstituteFederal University of Rio de JaneiroRio de JaneiroBrazil
| | - G. C. Atella
- Laboratory of Lipids and Lipoprotein BiochemistryBiochemistry InstituteFederal University of Rio de JaneiroRio de JaneiroBrazil
| | - P. L. Trindade
- Laboratory for studies of Interactions between Nutrition and GeneticsNutrition InstituteRio de Janeiro State UniversityRio de JaneiroBrazil
| | - J. B. Daleprane
- Laboratory for studies of Interactions between Nutrition and GeneticsNutrition InstituteRio de Janeiro State UniversityRio de JaneiroBrazil
| | - Elaine Oliveira
- Laboratory of Endocrine PhysiologyBiology InstituteState University of Rio de JaneiroRio de JaneiroBrazil
| | - Patricia Cristina Lisboa
- Laboratory of Endocrine PhysiologyBiology InstituteState University of Rio de JaneiroRio de JaneiroBrazil
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Rautmann AW, de La Serre CB. Microbiota's Role in Diet-Driven Alterations in Food Intake: Satiety, Energy Balance, and Reward. Nutrients 2021; 13:nu13093067. [PMID: 34578945 PMCID: PMC8470213 DOI: 10.3390/nu13093067] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 08/18/2021] [Accepted: 08/25/2021] [Indexed: 02/07/2023] Open
Abstract
The gut microbiota plays a key role in modulating host physiology and behavior, particularly feeding behavior and energy homeostasis. There is accumulating evidence demonstrating a role for gut microbiota in the etiology of obesity. In human and rodent studies, obesity and high-energy feeding are most consistently found to be associated with decreased bacterial diversity, changes in main phyla relative abundances and increased presence of pro-inflammatory products. Diet-associated alterations in microbiome composition are linked with weight gain, adiposity, and changes in ingestive behavior. There are multiple pathways through which the microbiome influences food intake. This review discusses these pathways, including peripheral mechanisms such as the regulation of gut satiety peptide release and alterations in leptin and cholecystokinin signaling along the vagus nerve, as well as central mechanisms, such as the modulation of hypothalamic neuroinflammation and alterations in reward signaling. Most research currently focuses on determining the role of the microbiome in the development of obesity and using microbiome manipulation to prevent diet-induced increase in food intake. More studies are necessary to determine whether microbiome manipulation after prolonged energy-dense diet exposure and obesity can reduce intake and promote meaningful weight loss.
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21
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Steenackers N, Wauters L, Van der Schueren B, Augustijns P, Falony G, Koziolek M, Lannoo M, Mertens A, Meulemans A, Raes J, Vangoitsenhoven R, Vieira-Silva S, Weitschies W, Matthys C, Vanuytsel T. Effect of obesity on gastrointestinal transit, pressure and pH using a wireless motility capsule. Eur J Pharm Biopharm 2021; 167:1-8. [PMID: 34273543 DOI: 10.1016/j.ejpb.2021.07.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 06/22/2021] [Accepted: 07/07/2021] [Indexed: 12/15/2022]
Abstract
BACKGROUND Despite the increasing prevalence and medical burden of obesity, the understanding of gastrointestinal physiology in obesity is scarce, which hampers drug development. AIM To investigate the effect of obesity and food intake on gastrointestinal transit, pressure and pH. MATERIAL AND METHODS An exploratory cross-sectional study using a wireless motility capsule (SmartPill©) was performed in 11 participants with obesity and 11 age- and gender-matched participants with normal weight (group) in fasted and fed state (visit). During the first visit, the capsule was ingested after an overnight fast. During a second visit, the capsule was ingested after a nutritional drink to simulate fed state. Linear mixed models were constructed to compare segmental gastrointestinal transit, pressure and pH between groups (obesity or control) and within every group (fasted or fed). RESULTS Food intake slowed gastric emptying in both groups (both P < 0.0001), though food-induced gastric contractility was higher in participants with obesity compared to controls (P = 0.02). In the small intestine, a higher contractility (P = 0.001), shorter transit (P = 0.04) and lower median pH (P = 0.002) was observed in participants with obesity compared to controls. No differences were observed for colonic measurements. CONCLUSION Obesity has a profound impact on gastrointestinal physiology, which should be taken into account for drug development.
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Affiliation(s)
- N Steenackers
- Clinical and Experimental Endocrinology, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium.
| | - L Wauters
- Translational Research Center for Gastrointestinal Disorders, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium.
| | - B Van der Schueren
- Clinical and Experimental Endocrinology, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium; Department of Endocrinology, University Hospitals Leuven, Leuven, Belgium.
| | - P Augustijns
- Drug Delivery and Disposition, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium.
| | - G Falony
- Rega Institute, Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium; Center for Microbiology, VIB, Leuven, Belgium.
| | - M Koziolek
- Institute of Pharmacy, Center of Drug Absorption and Transport, University of Greifswald, Greifswald, Germany.
| | - M Lannoo
- Department of Abdominal Surgery, University Hospitals Leuven, Leuven, Belgium.
| | - A Mertens
- Clinical and Experimental Endocrinology, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium; Department of Endocrinology, University Hospitals Leuven, Leuven, Belgium.
| | - A Meulemans
- Clinical and Experimental Endocrinology, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium; Department of Endocrinology, University Hospitals Leuven, Leuven, Belgium.
| | - J Raes
- Rega Institute, Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium; Center for Microbiology, VIB, Leuven, Belgium.
| | - R Vangoitsenhoven
- Clinical and Experimental Endocrinology, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium; Department of Endocrinology, University Hospitals Leuven, Leuven, Belgium.
| | - S Vieira-Silva
- Rega Institute, Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium; Center for Microbiology, VIB, Leuven, Belgium.
| | - W Weitschies
- Institute of Pharmacy, Center of Drug Absorption and Transport, University of Greifswald, Greifswald, Germany.
| | - C Matthys
- Clinical and Experimental Endocrinology, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium; Department of Endocrinology, University Hospitals Leuven, Leuven, Belgium.
| | - T Vanuytsel
- Translational Research Center for Gastrointestinal Disorders, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium; Department of Gastroenterology and Hepatology, University Hospitals Leuven, Leuven, Belgium.
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22
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Singh A, de Araujo AM, Krieger JP, Vergara M, Ip CK, de Lartigue G. Demystifying functional role of cocaine- and amphetamine-related transcript (CART) peptide in control of energy homeostasis: A twenty-five year expedition. Peptides 2021; 140:170534. [PMID: 33757831 PMCID: PMC8369463 DOI: 10.1016/j.peptides.2021.170534] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 02/28/2021] [Accepted: 03/16/2021] [Indexed: 12/17/2022]
Abstract
Cocaine- and amphetamine-related transcript (CART) is a neuropeptide first discovered in the striatum of the rat brain. Later, the genetic sequence and function of CART peptide (CARTp) was found to be conserved among multiple mammalian species. Over the 25 years, since its discovery, CART mRNA (Cartpt) expression has been reported widely throughout the central and peripheral nervous systems underscoring its role in diverse physiological functions. Here, we review the localization and function of CARTp as it relates to energy homeostasis. We summarize the expression changes of central and peripheral Cartpt in response to metabolic states and make use of available large data sets to gain additional insights into the anatomy of the Cartpt expressing vagal neurons and their expression patterns in the gut. Furthermore, we provide an overview of the role of CARTp as an anorexigenic signal and its effect on energy expenditure and body weight control with insights from both pharmacological and transgenic animal studies. Subsequently, we discuss the role of CARTp in the pathophysiology of obesity and review important new developments towards identifying a candidate receptor for CARTp signalling. Altogether, the field of CARTp research has made rapid and substantial progress recently, and we review the case for considering CARTp as a potential therapeutic target for stemming the obesity epidemic.
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Affiliation(s)
- Arashdeep Singh
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, USA; Center for Integrative Cardiovascular and Metabolic Disease, University of Florida, Gainesville, FL, USA
| | - Alan Moreira de Araujo
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, USA; Center for Integrative Cardiovascular and Metabolic Disease, University of Florida, Gainesville, FL, USA
| | - Jean-Philippe Krieger
- Department of Metabolic Physiology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Macarena Vergara
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, USA; Center for Integrative Cardiovascular and Metabolic Disease, University of Florida, Gainesville, FL, USA
| | - Chi Kin Ip
- Neuroscience Division, Garvan Institute of Medical Research, Darlinghurst, Sydney, Australia; Faculty of Medicine, University of New South Wales, Sydney, Australia
| | - Guillaume de Lartigue
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, USA; Center for Integrative Cardiovascular and Metabolic Disease, University of Florida, Gainesville, FL, USA.
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23
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Loper H, Leinen M, Bassoff L, Sample J, Romero-Ortega M, Gustafson KJ, Taylor DM, Schiefer MA. Both high fat and high carbohydrate diets impair vagus nerve signaling of satiety. Sci Rep 2021; 11:10394. [PMID: 34001925 PMCID: PMC8128917 DOI: 10.1038/s41598-021-89465-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 04/26/2021] [Indexed: 11/23/2022] Open
Abstract
Obesity remains prevalent in the US. One potential treatment is vagus nerve stimulation (VNS), which activates the sensory afferents innervating the stomach that convey stomach volume and establish satiety. However, current VNS approaches and stimulus optimization could benefit from additional understanding of the underlying neural response to stomach distension. In this study, obesity-prone Sprague Dawley rats consumed a standard, high-carbohydrate, or high-fat diet for several months, leading to diet-induced obesity in the latter two groups. Under anesthesia, the neural activity in the vagus nerve was recorded with a penetrating microelectrode array while the stomach was distended with an implanted balloon. Vagal tone during distension was compared to baseline tone prior to distension. Responses were strongly correlated with stomach distension, but the sensitivity to distension was significantly lower in animals that had been fed the nonstandard diets. The results indicate that both high fat and high carbohydrate diets impair vagus activity.
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Affiliation(s)
- Hailley Loper
- Malcom Randall VA Medical Center, Gainesville, FL, USA.,Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Monique Leinen
- Malcom Randall VA Medical Center, Gainesville, FL, USA.,Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Logan Bassoff
- Malcom Randall VA Medical Center, Gainesville, FL, USA.,Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Jack Sample
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA.,College of Medicine & Life Sciences, University of Toledo, Toledo, OH, USA
| | - Mario Romero-Ortega
- Departments of Biomedical Engineering and Biomedical Sciences, University of Houston, Houston, TX, USA
| | - Kenneth J Gustafson
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA.,Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Dawn M Taylor
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA.,Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA.,Department of Neurosciences, The Cleveland Clinic, Cleveland, OH, USA
| | - Matthew A Schiefer
- Malcom Randall VA Medical Center, Gainesville, FL, USA. .,Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA. .,Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA.
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24
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Clyburn C, Travagli RA, Arnold AC, Browning KN. DMV extrasynaptic NMDA receptors regulate caloric intake in rats. JCI Insight 2021; 6:139785. [PMID: 33764905 PMCID: PMC8262316 DOI: 10.1172/jci.insight.139785] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 03/24/2021] [Indexed: 11/17/2022] Open
Abstract
Acute high-fat diet (aHFD) exposure induces a brief period of hyperphagia before caloric balance is restored. Previous studies have demonstrated that this period of regulation is associated with activation of synaptic N-methyl-D-aspartate (NMDA) receptors on dorsal motor nucleus of the vagus (DMV) neurons, which increases vagal control of gastric functions. Our aim was to test the hypothesis that activation of DMV synaptic NMDA receptors occurs subsequent to activation of extrasynaptic NMDA receptors. Sprague-Dawley rats were fed a control or high-fat diet for 3-5 days prior to experimentation. Whole-cell patch-clamp recordings from gastric-projecting DMV neurons; in vivo recordings of gastric motility, tone, compliance, and emptying; and food intake studies were used to assess the effects of NMDA receptor antagonism on caloric regulation. After aHFD exposure, inhibition of extrasynaptic NMDA receptors prevented the synaptic NMDA receptor-mediated increase in glutamatergic transmission to DMV neurons, as well as the increase in gastric tone and motility, while chronic extrasynaptic NMDA receptor inhibition attenuated the regulation of caloric intake. After aHFD exposure, the regulation of food intake involved synaptic NMDA receptor-mediated currents, which occurred in response to extrasynaptic NMDA receptor activation. Understanding these events may provide a mechanistic basis for hyperphagia and may identify novel therapeutic targets for the treatment of obesity.
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25
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Browning KN, Carson KE. Central Neurocircuits Regulating Food Intake in Response to Gut Inputs-Preclinical Evidence. Nutrients 2021; 13:nu13030908. [PMID: 33799575 PMCID: PMC7998662 DOI: 10.3390/nu13030908] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 03/02/2021] [Accepted: 03/07/2021] [Indexed: 02/07/2023] Open
Abstract
The regulation of energy balance requires the complex integration of homeostatic and hedonic pathways, but sensory inputs from the gastrointestinal (GI) tract are increasingly recognized as playing critical roles. The stomach and small intestine relay sensory information to the central nervous system (CNS) via the sensory afferent vagus nerve. This vast volume of complex sensory information is received by neurons of the nucleus of the tractus solitarius (NTS) and is integrated with responses to circulating factors as well as descending inputs from the brainstem, midbrain, and forebrain nuclei involved in autonomic regulation. The integrated signal is relayed to the adjacent dorsal motor nucleus of the vagus (DMV), which supplies the motor output response via the efferent vagus nerve to regulate and modulate gastric motility, tone, secretion, and emptying, as well as intestinal motility and transit; the precise coordination of these responses is essential for the control of meal size, meal termination, and nutrient absorption. The interconnectivity of the NTS implies that many other CNS areas are capable of modulating vagal efferent output, emphasized by the many CNS disorders associated with dysregulated GI functions including feeding. This review will summarize the role of major CNS centers to gut-related inputs in the regulation of gastric function with specific reference to the regulation of food intake.
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26
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Understanding the appetite modulation pathways: The role of the FFA1 and FFA4 receptors. Biochem Pharmacol 2021; 186:114503. [PMID: 33711286 DOI: 10.1016/j.bcp.2021.114503] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 02/27/2021] [Accepted: 03/02/2021] [Indexed: 11/24/2022]
Abstract
Pharmaconutrition is an area of current interest, especially concerning the advances in the pharmacology of nutrient-sensing receptors, as have been accomplished in the last 20 years. The family of free fatty acid (FFA) receptors is composed of four members, sequentially named as FFA1 to FFA4, which are activated by the short to long-chain fatty acids. The affinity of the FFA1 and FFA4 receptors for the omega-3 polyunsaturated fatty acids prompted pre-clinical and clinical investigations regarding their involvement in metabolic diseases. The main studies have been focused on the receptors' expression analyses, the featuring of knockout mice, and the assessment of selective synthetic ligands. These clearly have indicated a relevant role for FFA1 and FFA4 in the peripheral and central circuits for the regulation of energetic metabolism. This review article aimed to discuss the relevance of the FFA1 and FFA4 receptors in appetite-related complications, mainly related to obesity, cancer cachexia, and anorexia in the elderly, emphasizing whether their pharmacological modulation might be useful for the management of these disorders.
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27
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Yosten GLC, Haddock CJ, Harada CM, Almeida-Pereira G, Kolar GR, Stein LM, Hayes MR, Salvemini D, Samson WK. Past, present and future of cocaine- and amphetamine-regulated transcript peptide. Physiol Behav 2021; 235:113380. [PMID: 33705816 DOI: 10.1016/j.physbeh.2021.113380] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 02/22/2021] [Accepted: 03/01/2021] [Indexed: 01/02/2023]
Abstract
The existence of the peptide encoded by the cocaine- and amphetamine-regulated transcript (Cartpt) has been recognized since 1981, but it was not until 1995, that the gene encoding CART peptide (CART) was identified. With the availability of the predicted protein sequence of CART investigators were able to identify sites of peptide localization, which then led to numerous approaches attempting to clarify CART's multiple pharmacologic effects and even provide evidence of potential physiologic relevance. Although not without controversy, a picture emerged of the importance of CART in ingestive behaviors, reward behaviors and even pain sensation. Despite the wealth of data hinting at the significance of CART, in the absence of an identified receptor, the full potential for this peptide or its analogs to be developed into therapeutic agents remained unrealized. There was evidence favoring the action of CART via a G protein-coupled receptor (GPCR), but despite multiple attempts the identity of that receptor eluded investigators until recently. Now with the identification of the previously orphaned GPCR, GPR160, as a receptor for CART, focus on this pluripotent neuropeptide will in all likelihood experience a renaissance and the potential for the development of pharmcotherapies targeting GPR160 seems within reach.
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Affiliation(s)
- Gina L C Yosten
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA; Henry and Nasrallah Center for Neuroscience, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Christopher J Haddock
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Caron M Harada
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA; Henry and Nasrallah Center for Neuroscience, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Gislaine Almeida-Pereira
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Grant R Kolar
- Henry and Nasrallah Center for Neuroscience, Saint Louis University School of Medicine, St. Louis, MO 63104, USA; Department of Pathology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Lauren M Stein
- Department of Psychiatry, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Matthew R Hayes
- Department of Psychiatry, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Daniela Salvemini
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA; Henry and Nasrallah Center for Neuroscience, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Willis K Samson
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA; Henry and Nasrallah Center for Neuroscience, Saint Louis University School of Medicine, St. Louis, MO 63104, USA.
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28
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Page AJ. Gastrointestinal Vagal Afferents and Food Intake: Relevance of Circadian Rhythms. Nutrients 2021; 13:nu13030844. [PMID: 33807524 PMCID: PMC7998414 DOI: 10.3390/nu13030844] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 02/25/2021] [Accepted: 03/03/2021] [Indexed: 01/20/2023] Open
Abstract
Gastrointestinal vagal afferents (VAs) play an important role in food intake regulation, providing the brain with information on the amount and nutrient composition of a meal. This is processed, eventually leading to meal termination. The response of gastric VAs, to food-related stimuli, is under circadian control and fluctuates depending on the time of day. These rhythms are highly correlated with meal size, with a nadir in VA sensitivity and increase in meal size during the dark phase and a peak in sensitivity and decrease in meal size during the light phase in mice. These rhythms are disrupted in diet-induced obesity and simulated shift work conditions and associated with disrupted food intake patterns. In diet-induced obesity the dampened responses during the light phase are not simply reversed by reverting back to a normal diet. However, time restricted feeding prevents loss of diurnal rhythms in VA signalling in high fat diet-fed mice and, therefore, provides a potential strategy to reset diurnal rhythms in VA signalling to a pre-obese phenotype. This review discusses the role of the circadian system in the regulation of gastrointestinal VA signals and the impact of factors, such as diet-induced obesity and shift work, on these rhythms.
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Affiliation(s)
- Amanda J. Page
- Adelaide Medical School, University of Adelaide, Adelaide, SA 5000, Australia; ; Tel.: +61-8-8128-4840
- Nutrition, Diabetes and Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institution (SAHMRI), Adelaide, SA 5000, Australia
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29
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McDougle M, Quinn D, Diepenbroek C, Singh A, de la Serre C, de Lartigue G. Intact vagal gut-brain signalling prevents hyperphagia and excessive weight gain in response to high-fat high-sugar diet. Acta Physiol (Oxf) 2021; 231:e13530. [PMID: 32603548 PMCID: PMC7772266 DOI: 10.1111/apha.13530] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 06/23/2020] [Accepted: 06/23/2020] [Indexed: 01/02/2023]
Abstract
Aim The tools that have been used to assess the function of the vagus nerve lack specificity. This could explain discrepancies about the role of vagal gut‐brain signalling in long‐term control of energy balance. Here we use a validated approach to selectively ablate sensory vagal neurones that innervate the gut to determine the role of vagal gut‐brain signalling in the control of food intake, energy expenditure and glucose homoeostasis in response to different diets. Methods Rat nodose ganglia were injected bilaterally with either the neurotoxin saporin conjugated to the gastrointestinal hormone cholecystokinin (CCK), or unconjugated saporin as a control. Food intake, body weight, glucose tolerance and energy expenditure were measured in both groups in response to chow or high‐fat high‐sugar (HFHS) diet. Willingness to work for fat or sugar was assessed by progressive ratio for orally administered solutions, while post‐ingestive feedback was tested by measuring food intake after an isocaloric lipid or sucrose pre‐load. Results Vagal deafferentation of the gut increases meal number in lean chow‐fed rats. Switching to a HFHS diet exacerbates overeating and body weight gain. The breakpoint for sugar or fat solution did not differ between groups, suggesting that increased palatability may not drive HFHS‐induced hyperphagia. Instead, decreased satiation in response to intra‐gastric infusion of fat, but not sugar, promotes hyperphagia in CCK‐Saporin‐treated rats fed with HFHS diet. Conclusions We conclude that intact sensory vagal neurones prevent hyperphagia and exacerbation of weight gain in response to a HFHS diet by promoting lipid‐mediated satiation.
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Affiliation(s)
- Molly McDougle
- Department of Pharmacodynamics University of Florida Gainesville FL USA
- Center for Integrative Cardiovascular and Metabolic Disease University of Florida Gainesville FL USA
- The John B. Pierce Laboratory New Haven CT USA
| | | | - Charlene Diepenbroek
- The John B. Pierce Laboratory New Haven CT USA
- Department of Cellular and Molecular Physiology Yale Medical School New Haven CT USA
| | - Arashdeep Singh
- Department of Pharmacodynamics University of Florida Gainesville FL USA
- Center for Integrative Cardiovascular and Metabolic Disease University of Florida Gainesville FL USA
| | | | - Guillaume de Lartigue
- Department of Pharmacodynamics University of Florida Gainesville FL USA
- Center for Integrative Cardiovascular and Metabolic Disease University of Florida Gainesville FL USA
- The John B. Pierce Laboratory New Haven CT USA
- Department of Cellular and Molecular Physiology Yale Medical School New Haven CT USA
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Orellana ER, Nyland JE, Horvath N, Hajnal A. Vagotomy increases alcohol intake in female rats in diet dependent manner: Implications for increased alcohol use disorder after roux-en-y gastric bypass surgery. Physiol Behav 2021; 235:113309. [PMID: 33412192 DOI: 10.1016/j.physbeh.2021.113309] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 12/18/2020] [Accepted: 12/31/2020] [Indexed: 12/25/2022]
Abstract
A variety of weight loss surgeries have been developed to fight the obesity epidemic, with Roux-en-Y gastric bypass (RYGB) being one of the most effective and popular procedures. However, the underlying mechanisms behind its efficacy are still not well understood. Furthermore, growing clinical evidence suggests that RYGB may result in increased risk for development of alcohol use disorder (AUD). The vagus nerve is a potentially critical contributor to increased risk of AUD following RYGB due to the potential for significant damage to the vagus during surgery, which has been confirmed in rodent studies. Studies aiming at the mechanisms underlying development of alcohol or substance use disorders following the surgery have exclusively used male rats, despite the majority of RYGB patients being female. Thus, the current study had two objectives: 1) to investigate the effect of RYGB on ethanol (EtOH) intake in female rats using a protocol previously established in male rats, and 2) to test the effect of vagal damage and high fat diet (HFD) on EtOH intake in female rats. In the first study, 22 female rats were maintained on HFD for four weeks and then split into two surgical groups, RYGB (n = 10) and Sham (n = 12). All rats then underwent a two-bottle choice test of increasing EtOH concentrations: 2%, 4%, 6%, 8%. Rats were then forced to abstain from EtOH for two weeks, after which access to 8% EtOH was reinstated. The RYGB female rats significantly increased their intake for low concentrations of EtOH (2% and 4%) and during the reinstatement period for 8%. These results mirror those seen in male rats, and thus, confirms RYGB in female rats as an equally viable model to males. In the second study, 40 female rats were separated into four groups: HFD/Sham, HFD/Vagotomy, normal diet (ND)/Sham, and ND/Vagotomy. All rats then were subjected to the same two-bottle choice test protocol as in the previous study. Rats in the vagotomy condition had significantly greater preference for 2% and 4% EtOH compared with Sham-operated controls. EtOH intake, either in ml or adjusted for body weight, was greater in rats maintained on ND compared with rats maintained on HFD. These data suggest that vagal damage may, at least in part, contribute to increased preference for EtOH. Furthermore, this increase in EtOH preference is counter to the blunting effect of HFD. In conclusion, the data presented here suggest a role for vagal damage in risk of AUD after weight loss surgery.
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Affiliation(s)
- Elise R Orellana
- The Pennsylvania State University College of Medicine, Department of Neural and Behavioral Sciences, United States.
| | - Jennifer E Nyland
- The Pennsylvania State University College of Medicine, Department of Neural and Behavioral Sciences, United States
| | - Nelli Horvath
- The Pennsylvania State University College of Medicine, Department of Neural and Behavioral Sciences, United States
| | - Andras Hajnal
- The Pennsylvania State University College of Medicine, Department of Neural and Behavioral Sciences, United States
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Li X, Wang H. Multiple organs involved in the pathogenesis of non-alcoholic fatty liver disease. Cell Biosci 2020; 10:140. [PMID: 33372630 PMCID: PMC7720519 DOI: 10.1186/s13578-020-00507-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 11/27/2020] [Indexed: 02/08/2023] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) represents the leading cause of chronic liver disease worldwide and the anticipated health burden is huge. There are limited therapeutic approaches for NAFLD now. It’s imperative to get a better understanding of the disease pathogenesis if new treatments are to be discovered. As the hepatic manifestation of metabolic syndrome, this disease involves complex interactions between different organs and regulatory pathways. It’s increasingly clear that brain, gut and adipose tissue all contribute to NAFLD pathogenesis and development, in view of their roles in energy homeostasis. In the present review, we try to summarize currently available data regarding NAFLD pathogenesis and to lay a particular emphasis on the inter-organ crosstalk evidence.
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Affiliation(s)
- Xiaoyan Li
- Department of Oncology, the First Affiliated Hospital of Anhui Medical University, Hefei, 230022, China
| | - Hua Wang
- Department of Oncology, the First Affiliated Hospital of Anhui Medical University, Hefei, 230022, China. .,Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Hefei, 230032, China.
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Xie H, Yepuri N, Meng Q, Dhawan R, Leech CA, Chepurny OG, Holz GG, Cooney RN. Therapeutic potential of α7 nicotinic acetylcholine receptor agonists to combat obesity, diabetes, and inflammation. Rev Endocr Metab Disord 2020; 21:431-447. [PMID: 32851581 PMCID: PMC7572644 DOI: 10.1007/s11154-020-09584-3] [Citation(s) in RCA: 20] [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] [Accepted: 08/21/2020] [Indexed: 12/12/2022]
Abstract
The cholinergic anti-inflammatory reflex (CAIR) represents an important homeostatic regulatory mechanism for sensing and controlling the body's response to inflammatory stimuli. Vagovagal reflexes are an integral component of CAIR whose anti-inflammatory effects are mediated by acetylcholine (ACh) acting at α7 nicotinic acetylcholine receptors (α7nAChR) located on cells of the immune system. Recently, it is appreciated that CAIR and α7nAChR also participate in the control of metabolic homeostasis. This has led to the understanding that defective vagovagal reflex circuitry underlying CAIR might explain the coexistence of obesity, diabetes, and inflammation in the metabolic syndrome. Thus, there is renewed interest in the α7nAChR that mediates CAIR, particularly from the standpoint of therapeutics. Of special note is the recent finding that α7nAChR agonist GTS-21 acts at L-cells of the distal intestine to stimulate the release of two glucoregulatory and anorexigenic hormones: glucagon-like peptide-1 (GLP-1) and peptide YY (PYY). Furthermore, α7nAChR agonist PNU 282987 exerts trophic factor-like actions to support pancreatic β-cell survival under conditions of stress resembling diabetes. This review provides an overview of α7nAChR function as it pertains to CAIR, vagovagal reflexes, and metabolic homeostasis. We also consider the possible usefulness of α7nAChR agonists for treatment of obesity, diabetes, and inflammation.
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Affiliation(s)
- Han Xie
- Departments of Surgery, State University of New York (SUNY), Upstate Medical University, 750 E Adams St., Suite 8141, Syracuse, NY, 13210, USA
| | - Natesh Yepuri
- Departments of Surgery, State University of New York (SUNY), Upstate Medical University, 750 E Adams St., Suite 8141, Syracuse, NY, 13210, USA
| | - Qinghe Meng
- Departments of Surgery, State University of New York (SUNY), Upstate Medical University, 750 E Adams St., Suite 8141, Syracuse, NY, 13210, USA
| | - Ravi Dhawan
- Departments of Surgery, State University of New York (SUNY), Upstate Medical University, 750 E Adams St., Suite 8141, Syracuse, NY, 13210, USA
| | - Colin A Leech
- Departments of Surgery, State University of New York (SUNY), Upstate Medical University, 750 E Adams St., Suite 8141, Syracuse, NY, 13210, USA
| | - Oleg G Chepurny
- Departments of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, NY, USA
| | - George G Holz
- Departments of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, NY, USA
| | - Robert N Cooney
- Departments of Surgery, State University of New York (SUNY), Upstate Medical University, 750 E Adams St., Suite 8141, Syracuse, NY, 13210, USA.
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Park SJ, Yu Y, Beyak MJ. Effect of high-fat diet on mechanosensitive transient receptor potential channel activation in vagal afferent neurons. Can J Physiol Pharmacol 2020; 99:660-666. [PMID: 33108741 DOI: 10.1139/cjpp-2020-0306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Mechanical stimulation of the gastrointestinal tract is an important stimulus of satiety and can be transduced by transient receptor potential (TRP) channels. Several studies have revealed attenuated vagally-mediated satiety responses including mechanosensitivity in diet-induced obesity; however, ion channels underlying this hyposensitivity have not been fully understood. This study aimed to examine the effect of chronic high-fat diet on activation of selected mechanosensitive TRP channels in vagal afferents. C57/BL6 mice were fed on either a high-fat or low-fat diet for 6-8 weeks. An increase in the intracellular calcium to hypotonic solution and activators of TRPV1, TRPV4, and TRPA1 was measured in nodose neurons using Ca2+-imaging techniques. Jejunal afferent nerve firing induced by mechanical stimulation and TRP channel agonists was measured using in vitro extracellular multiunit afferent recording. In high-fat diet-fed mice, we observed reduced calcium influx and jejunal afferent response induced by mechanical stimuli and agonists of TRPV4 and TRPA1, but not TRPV1. Our data show diet-induced obesity disrupts the activation of TRPV4 and TRPA1, at both the cellular level and the level of nerve terminals in the small intestine, which may partly explain reduced mechanosensitivity of vagal afferents and may contribute to decreased gut-brain satiety signaling in obesity.
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Affiliation(s)
- Sung Jin Park
- Gastrointestinal Diseases Research Unit, Kingston General Hospital, Queen's University, Kingston, ON, Canada.,Gastrointestinal Diseases Research Unit, Kingston General Hospital, Queen's University, Kingston, ON, Canada
| | - Yang Yu
- Gastrointestinal Diseases Research Unit, Kingston General Hospital, Queen's University, Kingston, ON, Canada.,Gastrointestinal Diseases Research Unit, Kingston General Hospital, Queen's University, Kingston, ON, Canada
| | - Michael J Beyak
- Gastrointestinal Diseases Research Unit, Kingston General Hospital, Queen's University, Kingston, ON, Canada.,Gastrointestinal Diseases Research Unit, Kingston General Hospital, Queen's University, Kingston, ON, Canada
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Lincoln KD. Race, Obesity, and Mental Health Among Older Adults in the United States: A Literature Review. Innov Aging 2020; 4:igaa031. [PMID: 32923693 PMCID: PMC7477914 DOI: 10.1093/geroni/igaa031] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Indexed: 12/24/2022] Open
Abstract
Rising rates of obesity among older adults in the United States are a serious public health concern. While the physical health consequences of obesity are well documented, the mental health consequences are less understood. This is especially the case among older adults in general and among racial and ethnic minority older adults in particular. Available studies document a link between obesity and a variety of mental health disorders. However, findings from this body of evidence are inconsistent, especially when race and ethnicity are considered. This article examines research on obesity and mental health among older adults and identifies risk factors, causal mechanisms, and methodological approaches that help clarify the equivocal nature of the literature. Promising research and future directions include studies that consider a wide array of contextual factors and population heterogeneity.
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Affiliation(s)
- Karen D Lincoln
- Suzanne Dworak-Peck School of Social Work, University of Southern California, Los Angeles
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Al Helaili A, Park SJ, Beyak MJ. Chronic high fat diet impairs glucagon like peptide-1 sensitivity in vagal afferents. Biochem Biophys Res Commun 2020; 533:110-117. [PMID: 32943186 DOI: 10.1016/j.bbrc.2020.08.045] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 08/16/2020] [Indexed: 12/11/2022]
Abstract
Dysfunction of the gut-brain axis is one of the potential contributors to the pathophysiology of obesity and is therefore a potential target for treatment. Vagal afferents innervating the gut play an important role in controlling energy homeostasis. There is an increasing evidence for the role of vagal afferents in mediating the anorexigenic effects of glucagon-like peptide-1 (GLP-1), an important satiety and incretin hormone. This study aimed to examine the effect of chronic high fat diet on GLP-1 sensitivity in vagal afferents. C57/BL6 mice were fed either a high-fat or low-fat diet for 6-8 weeks. To evaluate gastrointestinal afferent sensitivity and nodose neurons' response to GLP-1, extracellular afferent recordings and patch clamp were performed, respectively. Exendin-4 (Ex-4) was used as an agonist of the GLP-1 receptor. C-Fos Expression was examined as an indication of afferent input to the nucleus tractus solitarius (NTS). Food intake was monitored in real-time before and after Ex-4 treatment to monitor the consequence of the high fat diet on the satiating effect of GLP-1. In high fat fed (HFF) mice, GLP-1 caused lower activation of intestinal afferent nerves, and failed to potentiate mechanosensitive nerve responses compared to low fat fed (LFF). GLP-1 increased excitability in LFF and this effect was reduced in HFF neurons. Consistent with these findings on vagal afferent nerves, GLP-1 receptor stimulation given systemically, had a reduced satiating effect in HFF compared to LFF mice, and neuronal activation in the NTS was also reduced. The present study demonstrated chronic high fat diet impaired vagal afferent responses to GLP-1, resulting in impaired satiety signaling. GLP-1 sensitivity may account for the impairment of satiety signaling in obesity and thus a therapeutic target for obesity treatment.
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Affiliation(s)
- Alaa Al Helaili
- Mohammed Al Mana College for Medical Sciences, Abdulrazaq Bin Hammam Street, Al Safa, Dammam 34222, Saudi Arabia
| | - Sung Jin Park
- Gastrointestinal Disease Research Unit, Queen's University, Kingston, ON, K7L2V7, Canada
| | - Michael J Beyak
- Gastrointestinal Disease Research Unit, Queen's University, Kingston, ON, K7L2V7, Canada.
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Beutler LR, Corpuz TV, Ahn JS, Kosar S, Song W, Chen Y, Knight ZA. Obesity causes selective and long-lasting desensitization of AgRP neurons to dietary fat. eLife 2020; 9:e55909. [PMID: 32720646 PMCID: PMC7398661 DOI: 10.7554/elife.55909] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 07/20/2020] [Indexed: 12/12/2022] Open
Abstract
Body weight is regulated by interoceptive neural circuits that track energy need, but how the activity of these circuits is altered in obesity remains poorly understood. Here we describe the in vivo dynamics of hunger-promoting AgRP neurons during the development of diet-induced obesity in mice. We show that high-fat diet attenuates the response of AgRP neurons to an array of nutritionally-relevant stimuli including food cues, intragastric nutrients, cholecystokinin and ghrelin. These alterations are specific to dietary fat but not carbohydrate or protein. Subsequent weight loss restores the responsiveness of AgRP neurons to exterosensory cues but fails to rescue their sensitivity to gastrointestinal hormones or nutrients. These findings reveal that obesity triggers broad dysregulation of hypothalamic hunger neurons that is incompletely reversed by weight loss and may contribute to the difficulty of maintaining a reduced weight.
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Affiliation(s)
| | | | - Jamie S Ahn
- Howard Hughes Medical InstituteChevy ChaseUnited States
| | - Seher Kosar
- Howard Hughes Medical InstituteChevy ChaseUnited States
| | - Weimin Song
- Northwestern University Feinberg School of Medicine, Comprehensive Metabolic CoreChicagoUnited States
| | - Yiming Chen
- UCSF Department of PhysiologySan FranciscoUnited States
- UCSF Neuroscience Graduate ProgramSan FranciscoUnited States
| | - Zachary A Knight
- Howard Hughes Medical InstituteChevy ChaseUnited States
- UCSF Department of PhysiologySan FranciscoUnited States
- UCSF Neuroscience Graduate ProgramSan FranciscoUnited States
- Kavli Institute for Fundamental NeuroscienceSan FranciscoUnited States
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37
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Is cervical region tightness related to vagal function and stomach symptoms? Med Hypotheses 2020; 142:109819. [PMID: 32408072 DOI: 10.1016/j.mehy.2020.109819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 04/19/2020] [Accepted: 05/05/2020] [Indexed: 11/21/2022]
Abstract
The vagal nerve is a cranial nerve that carries mainly parasympathetic fibers (average 75%) with both sensory and motor functions. The vagal nerve contains a complex neuro-endocrine-immune network. The majority, at least 66%, of the gastric myenteric neurons receive direct cholinergic excitatory stimulation from the pre-enteric vagal nerve. Changes in vagal function may cause stomach problems, although the mechanisms that change the vagal function have not yet been fully illuminated. Considering the course of the vagal nerve in the cervical region, it is thought that conditions such as stiffness, tightness and decreased elasticity in this region may compress the vagal nerve andmay affect vagal function. According to this hypothesis, neuroinflammation and hyperalgesia may occur in the vagal nerve under mechanical pressure, resulting in increased complaints of pain and burning in the stomach increases. However, as the vagal nerve has various effects on the motility of the stomach and vagal dysfunction affects the motor function of the stomach, relaxation techniques applied to the soft tissues of the cervical region will provide mechanical relief in the nerve. Thus, the vagal nerve will be decompressed and be able to function optimally. According to our clinical observations, in patients whose soft tissues in the cervical region are relaxed, gastric symptoms are decreased. Based on research results and clinical experience, cervical region tightness can be considered to cause stomach problems through the vagal nerve, and soft tissue relaxation of the cervical region can be a promising treatment method for stomach symptoms.
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Jais A, Paeger L, Sotelo-Hitschfeld T, Bremser S, Prinzensteiner M, Klemm P, Mykytiuk V, Widdershooven PJM, Vesting AJ, Grzelka K, Minère M, Cremer AL, Xu J, Korotkova T, Lowell BB, Zeilhofer HU, Backes H, Fenselau H, Wunderlich FT, Kloppenburg P, Brüning JC. PNOC ARC Neurons Promote Hyperphagia and Obesity upon High-Fat-Diet Feeding. Neuron 2020; 106:1009-1025.e10. [PMID: 32302532 PMCID: PMC7303947 DOI: 10.1016/j.neuron.2020.03.022] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 03/11/2020] [Accepted: 03/23/2020] [Indexed: 12/30/2022]
Abstract
Calorie-rich diets induce hyperphagia and promote obesity, although the underlying mechanisms remain poorly defined. We find that short-term high-fat-diet (HFD) feeding of mice activates prepronociceptin (PNOC)-expressing neurons in the arcuate nucleus of the hypothalamus (ARC). PNOCARC neurons represent a previously unrecognized GABAergic population of ARC neurons distinct from well-defined feeding regulatory AgRP or POMC neurons. PNOCARC neurons arborize densely in the ARC and provide inhibitory synaptic input to nearby anorexigenic POMC neurons. Optogenetic activation of PNOCARC neurons in the ARC and their projections to the bed nucleus of the stria terminalis promotes feeding. Selective ablation of these cells promotes the activation of POMC neurons upon HFD exposure, reduces feeding, and protects from obesity, but it does not affect food intake or body weight under normal chow consumption. We characterize PNOCARC neurons as a novel ARC neuron population activated upon palatable food consumption to promote hyperphagia. Acute high-fat-diet feeding activates PNOC neurons in the arcuate nucleus (ARC) GABAergic PNOCARC neurons inhibit anorexigenic POMC neurons Optogenetic activation of PNOCARC neurons promotes feeding Ablation of PNOCARC neurons protects from obesity
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Affiliation(s)
- Alexander Jais
- Department of Neuronal Control of Metabolism, 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) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Lars Paeger
- Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Institute for Zoology, Biocenter, University of Cologne, Cologne, Germany
| | - Tamara Sotelo-Hitschfeld
- Department of Neuronal Control of Metabolism, 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) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Stephan Bremser
- Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Institute for Zoology, Biocenter, University of Cologne, Cologne, Germany
| | - Melanie Prinzensteiner
- Department of Neuronal Control of Metabolism, 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) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Paul Klemm
- Department of Neuronal Control of Metabolism, 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) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Vasyl Mykytiuk
- Neuronal Circuits and Behaviour Group, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany
| | - Pia J M Widdershooven
- Department of Neuronal Control of Metabolism, 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) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Anna Juliane Vesting
- 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) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany; Obesity and Cancer Group, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany
| | - Katarzyna Grzelka
- Synaptic Transmission in Energy Homeostasis Group, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany
| | - Marielle Minère
- Synaptic Transmission in Energy Homeostasis Group, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany
| | - Anna Lena Cremer
- Multimodal Imaging of Brain Metabolism Group, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany
| | - Jie Xu
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Tatiana Korotkova
- Neuronal Circuits and Behaviour Group, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany
| | - Bradford B Lowell
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA; Program in Neuroscience, Harvard Medical School, Boston, MA 02215, USA
| | - Hanns Ulrich Zeilhofer
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zurich, 8093 Zurich, Switzerland
| | - Heiko Backes
- Multimodal Imaging of Brain Metabolism Group, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany
| | - Henning Fenselau
- Center for Endocrinology, Diabetes, and Preventive Medicine (CEDP), University Hospital Cologne, Kerpener Strasse 26, 50924 Cologne, Germany; Synaptic Transmission in Energy Homeostasis Group, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany
| | - F Thomas Wunderlich
- 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) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany; Obesity and Cancer Group, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany
| | - Peter Kloppenburg
- Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Institute for Zoology, Biocenter, University of Cologne, Cologne, Germany.
| | - Jens C Brüning
- Department of Neuronal Control of Metabolism, 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) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany.
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Pradhananga S, Tashtush AA, Allen-Vercoe E, Petrof EO, Lomax AE. Protease-dependent excitation of nodose ganglion neurons by commensal gut bacteria. J Physiol 2020; 598:2137-2151. [PMID: 32134496 DOI: 10.1113/jp279075] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 02/28/2020] [Indexed: 12/19/2022] Open
Abstract
KEY POINTS The vagus nerve has been implicated in mediating behavioural effects of the gut microbiota on the central nervous system. This study examined whether the secretory products of commensal gut bacteria can modulate the excitability of vagal afferent neurons with cell bodies in nodose ganglia. Cysteine proteases from commensal bacteria increased the excitability of vagal afferent neurons via activation of protease-activated receptor 2 and modulation of the voltage dependence of Na+ conductance activation. Lipopolysaccharide, a component of the cell wall of gram-negative bacteria, increased the excitability of nodose ganglia neurons via TLR4-dependent activation of nuclear factor kappa B. Our study identified potential mechanisms by which gut microbiota influences the activity of vagal afferent pathways, which may in turn impact on autonomic reflexes and behaviour. ABSTRACT Behavioural studies have implicated vagal afferent neurons as an important component of the microbiota-gut-brain axis. However, the mechanisms underlying the ability of the gut microbiota to affect vagal afferent pathways are unclear. We examined the effect of supernatant from a community of 33 commensal gastrointestinal bacterial derived from a healthy human donor (microbial ecosystem therapeutics; MET-1) on the excitability of mouse vagal afferent neurons. Perforated patch clamp electrophysiology was used to measure the excitability of dissociated nodose ganglion (NG) neurons. NG neuronal excitability was assayed by measuring the amount of current required to elicit an action potential, the rheobase. MET-1 supernatant increased the excitability of NG neurons by hyperpolarizing the voltage dependence of activation of Na+ conductance. The increase in excitability elicited by MET-1 supernatant was blocked by the cysteine protease inhibitor E-64 (30 nm). The protease activated receptor-2 (PAR2 ) antagonist (GB 83, 10 μm) also blocked the effect of MET-1 supernatant on NG neurons. Supernatant from Lactobacillus paracasei 6MRS, a component of MET-1, recapitulated the effect of MET-1 supernatant on NG neurons. Lastly, we compared the effects of MET-1 supernatant and lipopolysaccharide (LPS) from Escherichia coli 05:B5 on NG neuron excitability. LPS increased the excitability of NG neurons in a toll-like receptor 4 (TLR4 )-dependent and PAR2 -independent manner, whereas the excitatory effects of MET-1 supernatant were independent of TLR4 activation. Together, our findings suggest that cysteine proteases from commensal bacteria increase the excitability of vagal afferent neurons by the activation of PAR2 .
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Affiliation(s)
- Sabindra Pradhananga
- Gastrointestinal Disease Research Unit (GIDRU), Queen's University, Kingston, Ontario, K7L2V7, Canada
| | - Ayssar A Tashtush
- Gastrointestinal Disease Research Unit (GIDRU), Queen's University, Kingston, Ontario, K7L2V7, Canada
| | - Emma Allen-Vercoe
- Department of Molecular and Cellular Biology, University of Guelph, Ontario, N1G2W1, Canada
| | - Elaine O Petrof
- Gastrointestinal Disease Research Unit (GIDRU), Queen's University, Kingston, Ontario, K7L2V7, Canada
| | - Alan E Lomax
- Gastrointestinal Disease Research Unit (GIDRU), Queen's University, Kingston, Ontario, K7L2V7, Canada
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2'-fucosyllactose Supplementation Improves Gut-Brain Signaling and Diet-Induced Obese Phenotype and Changes the Gut Microbiota in High Fat-Fed Mice. Nutrients 2020; 12:nu12041003. [PMID: 32260563 PMCID: PMC7231103 DOI: 10.3390/nu12041003] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 04/01/2020] [Accepted: 04/02/2020] [Indexed: 12/27/2022] Open
Abstract
Obesity is characterized by fat accumulation, chronic inflammation and impaired satiety signaling, which may be due in part to gut microbial dysbiosis. Manipulations of the gut microbiota and its metabolites are attractive targets for obesity treatment. The predominant oligosaccharide found in human milk, acts as a prebiotic with beneficial effects on the host. However, little is known about the beneficial effects of 2′-FL in obesity. The aim of this study was to determine the beneficial effects of 2′-FL supplementation on the microbiota-gut-brain axis and the diet-induced obese phenotype in high fat (HF)-fed mice. Male C57/BL6 mice (n = 6/group; six weeks old) were counter-balanced into six weight-matched groups and fed either a low-fat (LF; 10% kcal as fat), HF (45% kcal as fat) or HF diet with 2′-FL (HF_2′-FL) at 1, 2, 5 and 10% (w/v) in drinking water for six weeks. General phenotypes (body weight, energy intake, fat and lean mass), cecal microbiome and metabolites, gut-brain signaling, intestinal permeability and inflammatory and lipid profiles were assessed. Only 10% 2′-FL, but not 1, 2 or 5%, decreased HF diet-induced increases in energy intake, fat mass and body weight gain. A supplementation of 10% 2′-FL changed the composition of cecal microbiota and metabolites compared to LF- and HF-fed mice with an increase in Parabacteroides abundance and lactate and pyruvate, respectively, whose metabolic effects corresponded to our study findings. In particular, 10% 2′-FL significantly reversed the HF diet-induced impairment of cholecystokinin-induced inhibition of food intake. Gene expressions of interleukin (IL)-1β, IL-6, and macrophage chemoattractant protein-1 in the cecum were significantly downregulated by 10% 2′-FL compared to the HF group. Furthermore, 10% 2′-FL suppressed HF diet-induced upregulation of hepatic peroxisome proliferator-activated receptor gamma, a transcription factor for adipogenesis, at the gene level. In conclusion, 10% 2′-FL led to compositional changes in gut microbiota and metabolites associated with improvements in metabolic profiles and gut-brain signaling in HF-fed mice. These findings support the use of 2′-FL for modulating the hyperphagic response to HF diets and improving the microbiota-gut-brain axis.
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Lee SJ, Krieger JP, Vergara M, Quinn D, McDougle M, de Araujo A, Darling R, Zollinger B, Anderson S, Pan A, Simonnet EJ, Pignalosa A, Arnold M, Singh A, Langhans W, Raybould HE, de Lartigue G. Blunted Vagal Cocaine- and Amphetamine-Regulated Transcript Promotes Hyperphagia and Weight Gain. Cell Rep 2020; 30:2028-2039.e4. [PMID: 32049029 PMCID: PMC7063787 DOI: 10.1016/j.celrep.2020.01.045] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 12/06/2019] [Accepted: 01/15/2020] [Indexed: 12/31/2022] Open
Abstract
The vagus nerve conveys gastrointestinal cues to the brain to control eating behavior. In obesity, vagally mediated gut-brain signaling is disrupted. Here, we show that the cocaine- and amphetamine-regulated transcript (CART) is a neuropeptide synthesized proportional to the food consumed in vagal afferent neurons (VANs) of chow-fed rats. CART injection into the nucleus tractus solitarii (NTS), the site of vagal afferent central termination, reduces food intake. Conversely, blocking endogenous CART action in the NTS increases food intake in chow-fed rats, and this requires intact VANs. Viral-mediated Cartpt knockdown in VANs increases weight gain and daily food intake via larger meals and faster ingestion rate. In obese rats fed a high-fat, high-sugar diet, meal-induced CART synthesis in VANs is blunted and CART antibody fails to increase food intake. However, CART injection into the NTS retains its anorexigenic effect in obese rats. Restoring disrupted VAN CART signaling in obesity could be a promising therapeutic approach.
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Affiliation(s)
- Shin J Lee
- Physiology and Behavior Laboratory, ETH Zurich, Schwerzenbach, Switzerland
| | - Jean-Philippe Krieger
- Physiology and Behavior Laboratory, ETH Zurich, Schwerzenbach, Switzerland; Department of Metabolic Physiology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Macarena Vergara
- Department of Pharmacodynamics, Center for Integrative Cardiovascular and Metabolic Disease, University of Florida, Gainesville, FL, USA
| | | | - Molly McDougle
- Department of Pharmacodynamics, Center for Integrative Cardiovascular and Metabolic Disease, University of Florida, Gainesville, FL, USA; The John B. Pierce Laboratory, New Haven, CT, USA
| | - Alan de Araujo
- Department of Pharmacodynamics, Center for Integrative Cardiovascular and Metabolic Disease, University of Florida, Gainesville, FL, USA; The John B. Pierce Laboratory, New Haven, CT, USA; Yale University, New Haven, CT, USA
| | - Rebecca Darling
- Anatomy, Physiology and Cell Biology Department School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Benjamin Zollinger
- The John B. Pierce Laboratory, New Haven, CT, USA; Yale University, New Haven, CT, USA
| | - Seth Anderson
- The John B. Pierce Laboratory, New Haven, CT, USA; Yale University, New Haven, CT, USA
| | - Annabeth Pan
- The John B. Pierce Laboratory, New Haven, CT, USA; Yale University, New Haven, CT, USA
| | - Emilie J Simonnet
- Anatomy, Physiology and Cell Biology Department School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Angelica Pignalosa
- Physiology and Behavior Laboratory, ETH Zurich, Schwerzenbach, Switzerland
| | - Myrtha Arnold
- Physiology and Behavior Laboratory, ETH Zurich, Schwerzenbach, Switzerland
| | - Arashdeep Singh
- Department of Pharmacodynamics, Center for Integrative Cardiovascular and Metabolic Disease, University of Florida, Gainesville, FL, USA
| | - Wolfgang Langhans
- Physiology and Behavior Laboratory, ETH Zurich, Schwerzenbach, Switzerland
| | - Helen E Raybould
- Anatomy, Physiology and Cell Biology Department School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Guillaume de Lartigue
- Department of Pharmacodynamics, Center for Integrative Cardiovascular and Metabolic Disease, University of Florida, Gainesville, FL, USA; The John B. Pierce Laboratory, New Haven, CT, USA; Yale University, New Haven, CT, USA.
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Minaya DM, Di Lorenzo PM, Hajnal A, Czaja K. Roux-en-Y gastric bypass surgery triggers rapid DNA fragmentation in vagal afferent neurons in rats. Acta Neurobiol Exp (Wars) 2020. [DOI: 10.21307/ane-2019-040] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Browning KN. Stress-induced modulation of vagal afferents. Neurogastroenterol Motil 2019; 31:e13758. [PMID: 31736236 PMCID: PMC6986320 DOI: 10.1111/nmo.13758] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 10/18/2019] [Accepted: 10/18/2019] [Indexed: 12/13/2022]
Abstract
Vagally dependent gastric functions, including motility, tone, compliance, and emptying rate, play an important role in the regulation of food intake and satiation. Vagal afferent fibers relay sensory information from the stomach, including meal-related information, centrally and initiate co-ordinated autonomic efferent responses that regulate upper gastrointestinal responses. The purpose of this mini-review is to highlight several recent studies which have uncovered the remarkable degree of neuroplasticity within gastric mechanosensitive vagal afferents and the recent study by Li et al, in this issue of Neurogastroenterology and Motility, who show that the mechanosensitivity of gastric vagal afferents is dysregulated in a murine model of chronic stress. The authors demonstrate that both gastric mucosal and tension afferents are hypersensitive following chronic stress, and responses to mucosal stroking and muscle stretch are enhanced significantly. As gastric distension and volumetric signaling is important in satiety signaling and meal termination, this may provide a mechanistic basis for the gastric hypersensitivity associated with stress-associated clinical problems such as functional dyspepsia.
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Affiliation(s)
- Kirsteen N. Browning
- Department of Neural and Behavioral Sciences Penn State College of Medicine Hershey Pennsylvania
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Page AJ, Hatzinikolas G, Vincent AD, Cavuoto P, Wittert GA. The TRPV1 channel regulates glucose metabolism. Am J Physiol Endocrinol Metab 2019; 317:E667-E676. [PMID: 31408376 DOI: 10.1152/ajpendo.00102.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Endocannabinoids (ECs) mediate effects via cannabinoid receptor types 1 and 2 (CB1 and 2) and transient receptor potential channel-vanilloid subfamily member 1 (TRPV1) channels. In high-fat diet (HFD)-induced obese mice overactivity of the EC system and inhibition of CB1 increase skeletal muscle glucose uptake. We explored the role of TRPV1. Male TRPV1+/+(WT) and TRPV1-/-(KO)-mice were fed (20 wk) a standard laboratory diet (SLD) or HFD. An intraperitoneal glucose tolerance test was performed. RT-PCR was performed to measure mRNA of genes involved in glucose/lipid metabolism and the EC system in soleus (SOL) and extensor digitorum longus (EDL) muscles. Cultured L6 cells were used to measure glucose uptake in skeletal muscle. HFD mice weighed more and had higher insulin levels than SLD mice, with no genotype differences. Basal and peak glucose were higher in HFD mice irrespective of genotype, but glucose cleared faster in HFD WT vs. HFD KO-mice. 2-Arachidonoylglycerol augmented insulin-induced glucose uptake in skeletal L6-cells, an effect blocked by the TRPV1 antagonist SB-366791. In EDL, fatty acid amide hydrolase (FAAH) mRNA was increased in KO vs. WT mice, irrespective of diet. Pyruvate dehydrogenase kinase isozyme 4 (PDK4) and mitochondrial uncoupling protein 3 (UCP3) were elevated and FA desaturase 2 (FADS2) mRNA lower in HFD mice, irrespective of genotype. CB1 and stearoyl-CoA desaturase 1 (SCD1) were lower in HFD WT mice only. In SOL, PDK4, UCP3, hormone-sensitive lipase (LIPE), fatty acid translocase (CD36), and carnitine palmitoyl transferase 2 (CPT2) were elevated and SCD1, FAAH, FADS2, and Troponin 1 (TNNC1) mRNA lower in HFD mice, irrespective of genotype. In conclusion, TRPV1 regulates glucose disposal in HFD mice. We propose that TRPV1 plays a role in coordinating glucose metabolism in EDL under conditions of metabolic stress.
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Affiliation(s)
- Amanda J Page
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
- South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
- Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - George Hatzinikolas
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
- South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - Andrew D Vincent
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
- South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
- Freemasons Foundation Centre for Men's Health, University of Adelaide, Adelaide, South Australia, Australia
| | - Paul Cavuoto
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
| | - Gary A Wittert
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
- South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
- Freemasons Foundation Centre for Men's Health, University of Adelaide, Adelaide, South Australia, Australia
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Cryan JF, O'Riordan KJ, Cowan CSM, Sandhu KV, Bastiaanssen TFS, Boehme M, Codagnone MG, Cussotto S, Fulling C, Golubeva AV, Guzzetta KE, Jaggar M, Long-Smith CM, Lyte JM, Martin JA, Molinero-Perez A, Moloney G, Morelli E, Morillas E, O'Connor R, Cruz-Pereira JS, Peterson VL, Rea K, Ritz NL, Sherwin E, Spichak S, Teichman EM, van de Wouw M, Ventura-Silva AP, Wallace-Fitzsimons SE, Hyland N, Clarke G, Dinan TG. The Microbiota-Gut-Brain Axis. Physiol Rev 2019; 99:1877-2013. [DOI: 10.1152/physrev.00018.2018] [Citation(s) in RCA: 1243] [Impact Index Per Article: 248.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The importance of the gut-brain axis in maintaining homeostasis has long been appreciated. However, the past 15 yr have seen the emergence of the microbiota (the trillions of microorganisms within and on our bodies) as one of the key regulators of gut-brain function and has led to the appreciation of the importance of a distinct microbiota-gut-brain axis. This axis is gaining ever more traction in fields investigating the biological and physiological basis of psychiatric, neurodevelopmental, age-related, and neurodegenerative disorders. The microbiota and the brain communicate with each other via various routes including the immune system, tryptophan metabolism, the vagus nerve and the enteric nervous system, involving microbial metabolites such as short-chain fatty acids, branched chain amino acids, and peptidoglycans. Many factors can influence microbiota composition in early life, including infection, mode of birth delivery, use of antibiotic medications, the nature of nutritional provision, environmental stressors, and host genetics. At the other extreme of life, microbial diversity diminishes with aging. Stress, in particular, can significantly impact the microbiota-gut-brain axis at all stages of life. Much recent work has implicated the gut microbiota in many conditions including autism, anxiety, obesity, schizophrenia, Parkinson’s disease, and Alzheimer’s disease. Animal models have been paramount in linking the regulation of fundamental neural processes, such as neurogenesis and myelination, to microbiome activation of microglia. Moreover, translational human studies are ongoing and will greatly enhance the field. Future studies will focus on understanding the mechanisms underlying the microbiota-gut-brain axis and attempt to elucidate microbial-based intervention and therapeutic strategies for neuropsychiatric disorders.
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Affiliation(s)
- John F. Cryan
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Kenneth J. O'Riordan
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Caitlin S. M. Cowan
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Kiran V. Sandhu
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Thomaz F. S. Bastiaanssen
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Marcus Boehme
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Martin G. Codagnone
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Sofia Cussotto
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Christine Fulling
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Anna V. Golubeva
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Katherine E. Guzzetta
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Minal Jaggar
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Caitriona M. Long-Smith
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Joshua M. Lyte
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Jason A. Martin
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Alicia Molinero-Perez
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Gerard Moloney
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Emanuela Morelli
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Enrique Morillas
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Rory O'Connor
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Joana S. Cruz-Pereira
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Veronica L. Peterson
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Kieran Rea
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Nathaniel L. Ritz
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Eoin Sherwin
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Simon Spichak
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Emily M. Teichman
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Marcel van de Wouw
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Ana Paula Ventura-Silva
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Shauna E. Wallace-Fitzsimons
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Niall Hyland
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Gerard Clarke
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
| | - Timothy G. Dinan
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland; and Department of Physiology, University College Cork, Cork, Ireland
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Raka F, Farr S, Kelly J, Stoianov A, Adeli K. Metabolic control via nutrient-sensing mechanisms: role of taste receptors and the gut-brain neuroendocrine axis. Am J Physiol Endocrinol Metab 2019; 317:E559-E572. [PMID: 31310579 DOI: 10.1152/ajpendo.00036.2019] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Nutrient sensing plays an important role in ensuring that appropriate digestive or hormonal responses are elicited following the ingestion of fuel substrates. Mechanisms of nutrient sensing in the oral cavity have been fairly well characterized and involve lingual taste receptors. These include heterodimers of G protein-coupled receptors (GPCRs) of the taste receptor type 1 (T1R) family for sensing sweet (T1R2-T1R3) and umami (T1R1-T1R3) stimuli, the T2R family for sensing bitter stimuli, and ion channels for conferring sour and salty tastes. In recent years, several studies have revealed the existence of additional nutrient-sensing mechanisms along the gastrointestinal tract. Glucose sensing is achieved by the T1R2-T1R3 heterodimer on enteroendocrine cells, which plays a role in triggering the secretion of incretin hormones for improved glycemic and lipemic control. Protein hydrolysates are detected by Ca2+-sensing receptor, the T1R1-T1R3 heterodimer, and G protein-coupled receptor 92/93 (GPR92/93), which leads to the release of the gut-derived satiety factor cholecystokinin. Furthermore, several GPCRs have been implicated in fatty acid sensing: GPR40 and GPR120 respond to medium- and long-chain fatty acids, GPR41 and GPR43 to short-chain fatty acids, and GPR119 to endogenous lipid derivatives. Aside from the recognition of fuel substrates, both the oral cavity and the gastrointestinal tract also possess T2R-mediated mechanisms of recognizing nonnutrients such as environmental contaminants, bacterial toxins, and secondary plant metabolites that evoke a bitter taste. These gastrointestinal sensing mechanisms result in the transmission of neuronal signals to the brain through the release of gastrointestinal hormones that act on vagal and enteric afferents to modulate the physiological response to nutrients, particularly satiety and energy homeostasis. Modulating these orally accessible nutrient-sensing pathways using particular foods, dietary supplements, or pharmaceutical compounds may have therapeutic potential for treating obesity and metabolic diseases.
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Affiliation(s)
- Fitore Raka
- Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Sarah Farr
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Jacalyn Kelly
- Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Alexandra Stoianov
- Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Khosrow Adeli
- Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
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Grabauskas G, Wu X, Zhou S, Li J, Gao J, Owyang C. High-fat diet-induced vagal afferent dysfunction via upregulation of 2-pore domain potassium TRESK channel. JCI Insight 2019; 4:130402. [PMID: 31484832 DOI: 10.1172/jci.insight.130402] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 07/30/2019] [Indexed: 12/17/2022] Open
Abstract
Research shows that rats and humans on a high-fat diet (HFD) are less sensitive to satiety signals known to act via vagal afferent pathways. We hypothesize that HFD causes an upregulation of 2-pore domain potassium channels, resulting in hyperpolarization of nodose ganglia (NG) and decreased vagal response to satiety signals, which contribute to hyperphagia. We show that a 2-week HFD caused an upregulation of 2-pore domain TWIK-related spinal cord K+ (TRESK) and TWIK-related acid-sensitive K+ 1 (TASK1) channels by 330% ± 50% and 60% ± 20%, respectively, in NG. Patch-clamp studies of isolated NG neurons demonstrated a decrease in excitability. In vivo single-unit NG recordings showed that a 2-week HFD led to a 55% reduction in firing frequency in response to CCK-8 or leptin stimulation. NG electroporation with TRESK siRNA restored NG responsiveness to CCK-8 and leptin. Rats fed a 2-week HFD consumed ~40% more calories compared with controls. Silencing NG TRESK but not TASK1 channel expression in HFD-fed rats restored normal calorie consumption. In conclusion, HFD caused upregulation of TRESK channels, resulting in NG hyperpolarization and decreased vagal responsiveness to satiety signals. This finding provides a pharmacological target to prevent or treat HFD-induced hyperphagia.
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48
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Naukam RJ, Curtis KS. Estradiol and body weight during temporally targeted food restriction: Central pathways and peripheral metabolic factors. Horm Behav 2019; 115:104566. [PMID: 31422109 DOI: 10.1016/j.yhbeh.2019.104566] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 07/02/2019] [Accepted: 08/09/2019] [Indexed: 01/14/2023]
Abstract
We used temporally-targeted food restriction (TTFR), in which ovariectomized rats had chow only for 2 h/day, to test the hypothesis that estradiol benzoate (EB) suppresses feeding and decreases body weight during brief (4 day) TTFR, as it does during ad libitum feeding. All rats lost weight during TTFR, but the loss was greater with EB treatment. However, OIL and EB-treated rats ate comparable amounts of chow during TTFR. We next investigated central nervous system pathways and peripheral hormonal and metabolic changes that accompany the effects of TTFR to determine the mechanism for this effect. Immunolabeling for fos in the nucleus of the solitary tract, the terminal site of vagal afferents from the gastrointestinal tract, was increased when rats on TTFR had access to chow for 1 h on the test day, indicating neuronal activation associated with consumption of the meal. However, fos immunolabeling was not affected by EB treatment, nor were numbers of the α subtype of estrogen receptors. TTFR had the expected effects on carbohydrate and lipid metabolites and metabolic hormones, with only slight differences in plasma glucose, triglycerides, and free fatty acids attributable to EB treatment. Interestingly, plasma corticosterone levels were greater in EB-treated rats on TTFR, and increased further after eating. Given that corticosterone affects metabolism, these findings suggest that elevated corticosterone may explain the persistence of EB-induced differences in body weight during TTFR despite the lack of effect on food intake.
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Affiliation(s)
- Rebecca J Naukam
- Department of Pharmacology and Physiology, Oklahoma State University-Center for Health Sciences, Tulsa, OK 74107, USA
| | - Kathleen S Curtis
- Department of Pharmacology and Physiology, Oklahoma State University-Center for Health Sciences, Tulsa, OK 74107, USA.
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Yu Y, Villalobos-Hernandez EC, Pradhananga S, Baker CC, Keating C, Grundy D, Lomax AE, Reed DE. Deoxycholic acid activates colonic afferent nerves via 5-HT 3 receptor-dependent and -independent mechanisms. Am J Physiol Gastrointest Liver Physiol 2019; 317:G275-G284. [PMID: 31216174 DOI: 10.1152/ajpgi.00016.2019] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Increased bile acids in the colon can evoke increased epithelial secretion resulting in diarrhea, but little is known about whether colonic bile acids contribute to abdominal pain. This study aimed to investigate the mechanisms underlying activation of colonic extrinsic afferent nerves and their neuronal cell bodies by a major secondary bile acid, deoxycholic acid (DCA). All experiments were performed on male C57BL/6 mice. Afferent sensitivity was evaluated using in vitro extracellular recordings from mesenteric nerves in the proximal colon (innervated by vagal and spinal afferents) and distal colon (spinal afferents only). Neuronal excitability of cultured dorsal root ganglion (DRG) and nodose ganglion (NG) neurons was examined with perforated patch clamp. Colonic 5-HT release was assessed using ELISA, and 5-HT immunoreactive enterochromaffin (EC) cells were quantified. Intraluminal DCA increased afferent nerve firing rate concentration dependently in both proximal and distal colon. This DCA-elicited increase was significantly inhibited by a 5-HT3 antagonist in the proximal colon but not in the distal colon, which may be in part due to lower 5-HT immunoreactive EC cell density and lower 5-HT levels in the distal colon following DCA stimulation. DCA increased the excitability of DRG neurons, whereas it decreased the excitability of NG neurons. DCA potentiated mechanosensitivity of high-threshold spinal afferents independent of 5-HT release. Together, this study suggests that DCA can excite colonic afferents via direct and indirect mechanisms but the predominant mechanism may differ between vagal and spinal afferents. Furthermore, DCA increased mechanosensitivity of high-threshold spinal afferents and may be a mechanism of visceral hypersensitivity.NEW & NOTEWORTHY Deoxycholic acid (DCA) directly excites spinal afferents and, to a lesser extent, indirectly via mucosal 5-HT release. DCA potentiates mechanosensitivity of high-threshold spinal afferents independent of 5-HT release. DCA increases vagal afferent firing in proximal colon via 5-HT release but directly inhibits the excitability of their cell bodies.
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Affiliation(s)
- Yang Yu
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | | | - Sabindra Pradhananga
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Corey C Baker
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Christopher Keating
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - David Grundy
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Alan E Lomax
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - David E Reed
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
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50
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Clyburn C, Howe CA, Arnold AC, Lang CH, Travagli RA, Browning KN. Perinatal high-fat diet alters development of GABA A receptor subunits in dorsal motor nucleus of vagus. Am J Physiol Gastrointest Liver Physiol 2019; 317:G40-G50. [PMID: 31042399 PMCID: PMC6689732 DOI: 10.1152/ajpgi.00079.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 04/22/2019] [Accepted: 04/29/2019] [Indexed: 01/31/2023]
Abstract
Perinatal high-fat diet (pHFD) exposure increases the inhibition of dorsal motor nucleus of the vagus (DMV) neurons, potentially contributing to the dysregulation of gastric functions. The aim of this study was to test the hypothesis that pHFD increases the inhibition of DMV neurons by disrupting GABAA receptor subunit development. In vivo gastric recordings were made from adult anesthetized Sprague-Dawley rats fed a control or pHFD (14 or 60% kcal from fat, respectively) from embryonic day 13 (E13) to postnatal day 42 (P42), and response to brainstem microinjection of benzodiazepines was assessed. Whole cell patch clamp recordings from DMV neurons assessed the functional expression of GABAA α subunits, whereas mRNA and protein expression were measured via qPCR and Western blotting, respectively. pHFD decreased basal antrum and corpus motility, whereas brainstem microinjection of L838,417 (positive allosteric modulator of α2/3 subunit-containing GABAA receptors) produced a larger decrease in gastric tone and motility. GABAergic miniature inhibitory postsynaptic currents in pHFD DMV neurons were responsive to L838,417 throughout development, unlike control DMV neurons, which were responsive only at early postnatal timepoints. Brainstem mRNA and protein expression of the GABAA α1,2, and 3 subunits, however, did not differ between control and pHFD rats. This study suggests that pHFD exposure arrests the development of synaptic GABAA α2/3 receptor subunits on DMV neurons and that functional synaptic expression is maintained into adulthood, although cellular localization may differ. The tonic activation of slower GABAA α2/3 subunit-containing receptors implies that such developmental changes may contribute to the observed decreased gastric motility. NEW & NOTEWORTHY Vagal neurocircuits involved in the control of gastric functions, satiation, and food intake are subject to significant developmental regulation postnatally, with immature GABAA receptors expressing slower α2/3-subunits, whereas mature GABAA receptor express faster α1-subunits. After perinatal high-fat diet exposure, this developmental regulation of dorsal motor nucleus of the vagus (DMV) neurons is disrupted, increasing their tonic GABAergic inhibition, decreasing efferent output, and potentially decreasing gastric motility.
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Affiliation(s)
- Courtney Clyburn
- Department of Neural and Behavioral Sciences, Penn State College of Medicine , Hershey, Pennsylvania
| | - Caitlin A Howe
- Department of Neural and Behavioral Sciences, Penn State College of Medicine , Hershey, Pennsylvania
| | - Amy C Arnold
- Department of Neural and Behavioral Sciences, Penn State College of Medicine , Hershey, Pennsylvania
| | - Charles H Lang
- Department of Cellular and Molecular Physiology, Penn State College of Medicine , Hershey, Pennsylvania
| | - R Alberto Travagli
- Department of Neural and Behavioral Sciences, Penn State College of Medicine , Hershey, Pennsylvania
| | - Kirsteen N Browning
- Department of Neural and Behavioral Sciences, Penn State College of Medicine , Hershey, Pennsylvania
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