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Heni M. The insulin resistant brain: impact on whole-body metabolism and body fat distribution. Diabetologia 2024; 67:1181-1191. [PMID: 38363340 PMCID: PMC11153284 DOI: 10.1007/s00125-024-06104-9] [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: 07/21/2023] [Accepted: 12/19/2023] [Indexed: 02/17/2024]
Abstract
Insulin exerts its actions not only on peripheral organs but is also transported into the brain where it performs distinct functions in various brain regions. This review highlights recent advancements in our understanding of insulin's actions within the brain, with a specific emphasis on investigations in humans. It summarises current knowledge on the transport of insulin into the brain. Subsequently, it showcases robust evidence demonstrating the existence and physiological consequences of brain insulin action, while also introducing the presence of brain insulin resistance in humans. This pathophysiological condition goes along with an impaired acute modulation of peripheral metabolism in response to brain insulin action, particularly in the postprandial state. Furthermore, brain insulin resistance has been associated with long-term adiposity and an unfavourable adipose tissue distribution, thus implicating it in the pathogenesis of subgroups of obesity and (pre)diabetes that are characterised by distinct patterns of body fat distribution. Encouragingly, emerging evidence suggests that brain insulin resistance could represent a treatable entity, thereby opening up novel therapeutic avenues to improve systemic metabolism and enhance brain functions, including cognition. The review closes with an outlook towards prospective research directions aimed at further elucidating the clinical implications of brain insulin resistance. It emphasises the critical need to establish feasible diagnostic measures and effective therapeutic interventions.
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Affiliation(s)
- Martin Heni
- Division of Endocrinology and Diabetology, Department of Internal Medicine 1, University Hospital Ulm, Ulm, Germany.
- Department for Diagnostic Laboratory Medicine, Institute for Clinical Chemistry and Pathobiochemistry, University Hospital of Tübingen, Tübingen, Germany.
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2
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Gruber T, Lechner F, Krieger JP, García-Cáceres C. Neuroendocrine gut-brain signaling in obesity. Trends Endocrinol Metab 2024:S1043-2760(24)00120-6. [PMID: 38821753 DOI: 10.1016/j.tem.2024.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Revised: 04/29/2024] [Accepted: 05/03/2024] [Indexed: 06/02/2024]
Abstract
The past decades have witnessed the rise and fall of several, largely unsuccessful, therapeutic attempts to bring the escalating obesity pandemic to a halt. Looking back to look ahead, the field has now put its highest hopes in translating insights from how the gastrointestinal (GI) tract communicates with the brain to calibrate behavior, physiology, and metabolism. A major focus of this review is to summarize the latest advances in comprehending the neuroendocrine aspects of this so-called 'gut-brain axis' and to explore novel concepts, cutting-edge technologies, and recent paradigm-shifting experiments. These exciting insights continue to refine our understanding of gut-brain crosstalk and are poised to promote the development of additional therapeutic avenues at the dawn of a new era of antiobesity therapeutics.
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Affiliation(s)
- Tim Gruber
- 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; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany.
| | - Franziska Lechner
- German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany; Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany
| | - Jean-Philippe Krieger
- Institute of Veterinary Pharmacology and Toxicology, University of Zurich-Vetsuisse, 8057 Zurich, Switzerland; Institute of Neuroscience and Physiology, University of Gothenburg, 40530 Gothenburg, Sweden
| | - Cristina García-Cáceres
- German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany; Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany; Medizinische Klinik und Poliklinik IV, Klinikum der Universität, Ludwig-Maximilians-Universität München, 80336 Munich, Germany.
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3
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Buller S, Blouet C. Brain access of incretins and incretin receptor agonists to their central targets relevant for appetite suppression and weight loss. Am J Physiol Endocrinol Metab 2024; 326:E472-E480. [PMID: 38381398 DOI: 10.1152/ajpendo.00250.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 01/05/2024] [Accepted: 02/13/2024] [Indexed: 02/22/2024]
Abstract
New incretin-based pharmacotherapies provide efficient and safe therapeutic options to curb appetite and produce weight loss in patients with obesity. Delivered systemically, these molecules produce pleiotropic metabolic benefits, but the target sites mediating their weight-suppressive action are located within the brain. Recent research has increased our understanding of the neural circuits and behavioral mechanisms involved in the anorectic and metabolic consequences of glucagon-like peptide 1 (GLP-1)-based weight loss strategies, yet little is known about how these drugs access their functional targets in the brain to produce sustained weight loss. The majority of brain cells expressing incretin receptors are located behind the blood-brain barrier, shielded from the circulation and fluctuations in the availability of peripheral signals, which is a major challenge for the development of CNS-targeted therapeutic peptides. GLP-1 receptor (GLP-1R) agonists with increased half-life and enhanced therapeutic benefit do not cross the blood-brain barrier, yet they manage to access discrete brain sites relevant to the regulation of energy homeostasis. In this review, we give a brief overview of the different routes for peptide hormones to access the brain. We then examine the evidence informing the routes employed by incretins and incretin receptor agonists to access brain targets relevant for their appetite and weight-suppressive actions. We highlight existing controversies and suggest future directions to further establish the functionally relevant access routes for GLP-1-based weight loss compounds, which might guide the development and selection of the future generation of incretin receptor polypharmacologies.
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Affiliation(s)
- Sophie Buller
- Medical Research Council (MRC) Metabolic Diseases Unit, Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
| | - Clemence Blouet
- Medical Research Council (MRC) Metabolic Diseases Unit, Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
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López-Gambero AJ, Jouque V, Cota D. A sympathetic brake on gut GLP-1 release. Neuron 2024; 112:865-867. [PMID: 38513615 DOI: 10.1016/j.neuron.2024.02.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 02/16/2024] [Accepted: 02/16/2024] [Indexed: 03/23/2024]
Abstract
The brain-gut neurocircuitry is proving to be finely involved in a wide range of physiological functions. In this issue of Neuron, Ren et al.1 show that adrenergic signaling suppresses postprandial glucagon-like peptide 1 (GLP-1) secretion. This, in turn, raises circulating glucose levels and impairs brain glucose uptake and cognitive function.
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Affiliation(s)
| | - Victor Jouque
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-33000 Bordeaux, France
| | - Daniela Cota
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-33000 Bordeaux, France.
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5
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Allard C, Cota D, Quarta C. Poly-Agonist Pharmacotherapies for Metabolic Diseases: Hopes and New Challenges. Drugs 2024; 84:127-148. [PMID: 38127286 DOI: 10.1007/s40265-023-01982-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/26/2023] [Indexed: 12/23/2023]
Abstract
The use of glucagon-like peptide-1 (GLP-1) receptor-based multi-agonists in the treatment of type 2 diabetes and obesity holds great promise for improving glycaemic control and weight management. Unimolecular dual and triple agonists targeting multiple gut hormone-related pathways are currently in clinical trials, with recent evidence supporting their efficacy. However, significant knowledge gaps remain regarding the biological mechanisms and potential adverse effects associated with these multi-target agents. The mechanisms underlying the therapeutic efficacy of GLP-1 receptor-based multi-agonists remain somewhat mysterious, and hidden threats may be associated with the use of gut hormone-based polyagonists. In this review, we provide a critical analysis of the benefits and risks associated with the use of these new drugs in the management of obesity and diabetes, while also exploring new potential applications of GLP-1-based pharmacology beyond the field of metabolic disease.
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Affiliation(s)
- Camille Allard
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, 33000, Bordeaux, France
| | - Daniela Cota
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, 33000, Bordeaux, France
| | - Carmelo Quarta
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, 33000, Bordeaux, France.
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Brüning JC, Fenselau H. Integrative neurocircuits that control metabolism and food intake. Science 2023; 381:eabl7398. [PMID: 37769095 DOI: 10.1126/science.abl7398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 08/31/2023] [Indexed: 09/30/2023]
Abstract
Systemic metabolism has to be constantly adjusted to the variance of food intake and even be prepared for anticipated changes in nutrient availability. Therefore, the brain integrates multiple homeostatic signals with numerous cues that predict future deviations in energy supply. Recently, our understanding of the neural pathways underlying these regulatory principles-as well as their convergence in the hypothalamus as the key coordinator of food intake, energy expenditure, and glucose metabolism-have been revealed. These advances have changed our view of brain-dependent control of metabolic physiology. In this Review, we discuss new concepts about how alterations in these pathways contribute to the development of prevalent metabolic diseases such as obesity and type 2 diabetes mellitus and how this emerging knowledge may provide new targets for their treatment.
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Affiliation(s)
- Jens C Brüning
- Department of Neuronal Control of Metabolism, Max Planck Institute for Metabolism Research, 50931 Cologne, Germany
- Policlinic for Endocrinology, Diabetes, and Preventive Medicine (PEDP), University Hospital Cologne, 50924 Cologne, Germany
- Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
- National Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Henning Fenselau
- Policlinic for Endocrinology, Diabetes, and Preventive Medicine (PEDP), University Hospital Cologne, 50924 Cologne, Germany
- Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
- Research Group Synaptic Transmission in Energy Homeostasis, Max Planck Institute for Metabolism Research, 50931 Cologne, Germany
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7
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Skovbjerg G, Roostalu U, Salinas CG, Skytte JL, Perens J, Clemmensen C, Elster L, Frich CK, Hansen HH, Hecksher-Sørensen J. Uncovering CNS access of lipidated exendin-4 analogues by quantitative whole-brain 3D light sheet imaging. Neuropharmacology 2023:109637. [PMID: 37391028 DOI: 10.1016/j.neuropharm.2023.109637] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 06/07/2023] [Accepted: 06/09/2023] [Indexed: 07/02/2023]
Abstract
Peptide-based drug development for CNS disorders is challenged by poor blood-brain barrier (BBB) penetrability of peptides. While acylation protractions (lipidation) have been successfully applied to increase circulating half-life of therapeutic peptides, little is known about the CNS accessibility of lipidated peptide drugs. Light-sheet fluorescence microscopy (LSFM) has emerged as a powerful method to visualize whole-brain 3D distribution of fluorescently labelled therapeutic peptides at single-cell resolution. Here, we applied LSFM to map CNS distribution of the clinically relevant GLP-1 receptor agonist (GLP-1RA) exendin-4 (Ex4) and lipidated analogues following peripheral administration. Mice received an intravenous dose (100 nmol/kg) of IR800 fluorophore-labelled Ex4 (Ex4), Ex4 acylated with a C16-monoacid (Ex4_C16MA) or C18-diacid (Ex4_C18DA). Other mice were administered C16MA-acylated exendin 9-39 (Ex9-39_C16MA), a selective GLP-1R antagonist, serving as negative control for GLP-1R mediated agonist internalization. Two hours post-dosing, brain distribution of Ex4 and analogues was predominantly restricted to the circumventricular organs, notably area postrema and nucleus of the solitary tract. Ex4_C16MA and Ex9-39_C16MA also distributed to the paraventricular hypothalamic nucleus and medial habenula. Notably, Ex4_C18DA was detected in deeper-lying brain structures such as dorsomedial/ventromedial hypothalamic nuclei and the dentate gyrus. Similar CNS distribution maps of Ex4-C16MA and Ex9-39_C16MA suggest that brain access of lipidated Ex4 analogues is independent on GLP-1 receptor internalization. The cerebrovasculature was devoid of specific labelling, hence not supporting a direct role of GLP-1 RAs in BBB function. In conclusion, peptide lipidation increases CNS accessibility of Ex4. Our fully automated LSFM pipeline is suitable for mapping whole-brain distribution of fluorescently labelled drugs.
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Affiliation(s)
- Grethe Skovbjerg
- Gubra ApS, Hørsholm Kongevej 11B, 2970, Hørsholm, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Denmark
| | - Urmas Roostalu
- Gubra ApS, Hørsholm Kongevej 11B, 2970, Hørsholm, Denmark
| | | | - Jacob L Skytte
- Gubra ApS, Hørsholm Kongevej 11B, 2970, Hørsholm, Denmark
| | - Johanna Perens
- Gubra ApS, Hørsholm Kongevej 11B, 2970, Hørsholm, Denmark
| | - Christoffer Clemmensen
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Denmark
| | - Lisbeth Elster
- Gubra ApS, Hørsholm Kongevej 11B, 2970, Hørsholm, Denmark
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