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Quenneville S, Labouèbe G, Basco D, Metref S, Viollet B, Foretz M, Thorens B. Hypoglycemia-Sensing Neurons of the Ventromedial Hypothalamus Require AMPK-Induced Txn2 Expression but Are Dispensable for Physiological Counterregulation. Diabetes 2020; 69:2253-2266. [PMID: 32839348 PMCID: PMC7576557 DOI: 10.2337/db20-0577] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 08/18/2020] [Indexed: 12/23/2022]
Abstract
The ventromedial nucleus of the hypothalamus (VMN) is involved in the counterregulatory response to hypoglycemia. VMN neurons activated by hypoglycemia (glucose-inhibited [GI] neurons) have been assumed to play a critical although untested role in this response. Here, we show that expression of a dominant negative form of AMPK or inactivation of AMPK α1 and α2 subunit genes in Sf1 neurons of the VMN selectively suppressed GI neuron activity. We found that Txn2, encoding a mitochondrial redox enzyme, was strongly downregulated in the absence of AMPK activity and that reexpression of Txn2 in Sf1 neurons restored GI neuron activity. In cell lines, Txn2 was required to limit glucopenia-induced reactive oxygen species production. In physiological studies, absence of GI neuron activity after AMPK suppression in the VMN had no impact on the counterregulatory hormone response to hypoglycemia or on feeding. Thus, AMPK is required for GI neuron activity by controlling the expression of the antioxidant enzyme Txn2. However, the glucose-sensing capacity of VMN GI neurons is not required for the normal counterregulatory response to hypoglycemia. Instead, it may represent a fail-safe system in case of impaired hypoglycemia sensing by peripherally located glucose detection systems that are connected to the VMN.
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Affiliation(s)
- Simon Quenneville
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Gwenaël Labouèbe
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Davide Basco
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Salima Metref
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Benoit Viollet
- Université de Paris, Institut Cochin, CNRS, INSERM, Paris, France
| | - Marc Foretz
- Université de Paris, Institut Cochin, CNRS, INSERM, Paris, France
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
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Wu X, Yang P, Sifa D, Wen Z. Effect of dietary stevioside supplementation on growth performance, nutrient digestibility, serum parameters, and intestinal microflora in broilers. Food Funct 2019; 10:2340-2346. [PMID: 31020296 DOI: 10.1039/c8fo01883a] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Disinhibition of antibiotics promotes the use of probiotics, prebiotics, immune enhancers, and plant extracts. We investigated the effects of stevioside on growth performance, nutrient digestibility, serum parameters, and intestinal microflora in broilers. Eight hundred ninety-six one-day-old male Arbor Acres broiler chicks (average body weight 48.36 ± 0.21 g) were allotted to 1 of 7 experimental treatments. Treatments consisted of: (1) control (basal diet without supplemental stevioside), (2) 100 mg kg-1 supplemental stevioside (S100), (3) 200 mg kg-1 supplemental stevioside (S200), (4) 400 mg kg-1 supplemental stevioside (S400), (5) 800 mg kg-1 supplemental stevioside (S800), (6) 1600 mg kg-1 supplemental stevioside (S1600), and (7) 3200 mg kg-1 supplemental stevioside (S3200). Performance was not affected by stevioside concentration. Dietary stevioside supplementation increased the digestibility of calcium (P < 0.05) and tended to improve phosphorus digestibility (P = 0.0730). There was a linear effect of dietary stevioside on the concentration of serum glucose (P < 0.05). The serum IgG and IgA levels were linearly increased by stevioside supplementation (P < 0.05). In the ileal digesta, the concentration of E. coli decreased with increasing dietary stevioside supplementation (P < 0.05). On the contrary, dietary stevioside supplementation increased the concentration of Bifidobacteria (P < 0.01) and tended to improve the concentration of Lactobacillus (P = 0.0791). In conclusion, our data suggest that stevioside supplementation could improve the calcium and phosphorus digestibility and decrease blood glucose levels of broilers. Additionally, dietary stevioside supplementation significantly increased Bifidobacteria in the cecal digesta, and decreased E. coli.
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Affiliation(s)
- Xuezhuang Wu
- College of Animal Science, Anhui Science and Technology University, Bengbu, 233100, People's Republic of China.
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Quarta C, Fioramonti X, Cota D. POMC Neurons Dysfunction in Diet-induced Metabolic Disease: Hallmark or Mechanism of Disease? Neuroscience 2019; 447:3-14. [PMID: 31689486 DOI: 10.1016/j.neuroscience.2019.09.031] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 09/19/2019] [Accepted: 09/24/2019] [Indexed: 12/19/2022]
Abstract
One important lesson from the last decade of studies in the field of systemic energy metabolism is that obesity is first and foremost a brain disease. Hypothalamic neurons dysfunction observed in response to chronic metabolic stress is a key pathogenic node linking consumption of hypercaloric diets with body weight gain and associated metabolic sequelae. A key hypothalamic neuronal population expressing the neuropeptide Pro-opio-melanocortin (POMC) displays altered electrical activity and dysregulated neuropeptides production capacity after long-term feeding with hypercaloric diets. However, whether such neuronal dysfunction represents a consequence or a mechanism of disease, remains a subject of debate. Here, we will review and highlight emerging pathogenic mechanisms that explain why POMC neurons undergo dysfunctional activity in response to caloric overload, and critically address whether these mechanisms may be causally implicated in the physiopathology of obesity and of its associated co-morbidities.
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Affiliation(s)
- Carmelo Quarta
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France.
| | - Xavier Fioramonti
- Université de Bordeaux, Institut National de la Recherche Agronomique, Bordeaux INP, NutriNeuro, UMR 1286, F-33000 Bordeaux, France
| | - Daniela Cota
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France.
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Haissaguerre M, Ferrière A, Simon V, Saucisse N, Dupuy N, André C, Clark S, Guzman-Quevedo O, Tabarin A, Cota D. mTORC1-dependent increase in oxidative metabolism in POMC neurons regulates food intake and action of leptin. Mol Metab 2018; 12:98-106. [PMID: 29699927 PMCID: PMC6001919 DOI: 10.1016/j.molmet.2018.04.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 04/05/2018] [Accepted: 04/07/2018] [Indexed: 01/19/2023] Open
Abstract
OBJECTIVE Nutrient availability modulates reactive oxygen species (ROS) production in the hypothalamus. In turn, ROS regulate hypothalamic neuronal activity and feeding behavior. The mechanistic target of rapamycin complex 1 (mTORC1) pathway is an important cellular integrator of the action of nutrients and hormones. Here we tested the hypothesis that modulation of mTORC1 activity, particularly in Proopiomelanocortin (POMC)-expressing neurons, mediates the cellular and behavioral effects of ROS. METHODS C57BL/6J mice or controls and their knockout (KO) littermates deficient either for the mTORC1 downstream target 70-kDa ribosomal protein S6 kinase 1 (S6K1) or for the mTORC1 component Rptor specifically in POMC neurons (POMC-rptor-KO) were treated with an intracerebroventricular (icv) injection of the ROS hydrogen peroxide (H2O2) or the ROS scavenger honokiol, alone or, respectively, in combination with the mTORC1 inhibitor rapamycin or the mTORC1 activator leptin. Oxidant-related signal in POMC neurons was assessed using dihydroethidium (DHE) fluorescence. RESULTS Icv administration of H2O2 decreased food intake, while co-administration of rapamycin, whole-body deletion of S6K1, or deletion of rptor in POMC neurons impeded the anorectic action of H2O2. H2O2 also increased oxidant levels in POMC neurons, an effect that hinged on functional mTORC1 in these neurons. Finally, scavenging ROS prevented the hypophagic action of leptin, which in turn required mTORC1 to increase oxidant levels in POMC neurons and to inhibit food intake. CONCLUSIONS Our results demonstrate that ROS and leptin require mTORC1 pathway activity in POMC neurons to increase oxidant levels in POMC neurons and consequently decrease food intake.
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Affiliation(s)
- Magalie Haissaguerre
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; Department of Endocrinology, Hôpital Haut Lévèque, CHU Bordeaux, F-33600 Pessac, France
| | - Amandine Ferrière
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; Department of Endocrinology, Hôpital Haut Lévèque, CHU Bordeaux, F-33600 Pessac, France
| | - Vincent Simon
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France
| | - Nicolas Saucisse
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France
| | - Nathalie Dupuy
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France
| | - Caroline André
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France
| | - Samantha Clark
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France
| | - Omar Guzman-Quevedo
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France
| | - Antoine Tabarin
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; Department of Endocrinology, Hôpital Haut Lévèque, CHU Bordeaux, F-33600 Pessac, France
| | - Daniela Cota
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France.
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Burke LK, Ogunnowo-Bada E, Georgescu T, Cristiano C, de Morentin PBM, Valencia Torres L, D'Agostino G, Riches C, Heeley N, Ruan Y, Rubinstein M, Low MJ, Myers MG, Rochford JJ, Evans ML, Heisler LK. Lorcaserin improves glycemic control via a melanocortin neurocircuit. Mol Metab 2017; 6:1092-1102. [PMID: 29031711 PMCID: PMC5641625 DOI: 10.1016/j.molmet.2017.07.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 07/05/2017] [Accepted: 07/10/2017] [Indexed: 02/07/2023] Open
Abstract
Objective The increasing prevalence of type 2 diabetes (T2D) and associated morbidity and mortality emphasizes the need for a more complete understanding of the mechanisms mediating glucose homeostasis to accelerate the identification of new medications. Recent reports indicate that the obesity medication lorcaserin, a 5-hydroxytryptamine (5-HT, serotonin) 2C receptor (5-HT2CR) agonist, improves glycemic control in association with weight loss in obese patients with T2D. Here we evaluate whether lorcaserin has an effect on glycemia without body weight loss and how this effect is achieved. Methods Murine models of common and genetic T2D were utilized to probe the direct effect of lorcaserin on glycemic control. Results Lorcaserin dose-dependently improves glycemic control in mouse models of T2D in the absence of reductions in food intake or body weight. Examining the mechanism of this effect, we reveal a necessary and sufficient neurochemical mediator of lorcaserin's glucoregulatory effects, brain pro-opiomelanocortin (POMC) peptides. To clarify further lorcaserin's therapeutic brain circuit, we examined the receptor target of POMC peptides. We demonstrate that lorcaserin requires functional melanocortin4 receptors on cholinergic preganglionic neurons (MC4RChAT) to exert its effects on glucose homeostasis. In contrast, MC4RChAT signaling did not impact lorcaserin's effects on feeding, indicating a divergence in the neurocircuitry underpinning lorcaserin's therapeutic glycemic and anorectic effects. Hyperinsulinemic-euglycemic clamp studies reveal that lorcaserin reduces hepatic glucose production, increases glucose disposal and improves insulin sensitivity. Conclusions These data suggest that lorcaserin's action within the brain represents a mechanistically novel treatment for T2D: findings of significance to a prevalent global disease. Obesity medication lorcaserin directly improves glycemic control without altering energy balance or body weight. Unlike current frontline type 2 diabetes medications, lorcaserin acts within the brain to improve glycemic control. Brain Pro-opiomelanocortin (POMC) peptides are a neurochemical mediator of lorcaserin's glucoregulatory effects. Lorcaserin increases insulin sensitivity, reduces hepatic glucose production and increases glucose disposal.
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Affiliation(s)
- Luke K Burke
- Department of Pharmacology, University of Cambridge, Cambridge, UK; Department of Medicine and Wellcome Trust/MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Emmanuel Ogunnowo-Bada
- Department of Medicine and Wellcome Trust/MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | | | | | | | - Lourdes Valencia Torres
- Department of Pharmacology, University of Cambridge, Cambridge, UK; The Rowett Institute, University of Aberdeen, Aberdeen, UK
| | - Giuseppe D'Agostino
- Department of Pharmacology, University of Cambridge, Cambridge, UK; The Rowett Institute, University of Aberdeen, Aberdeen, UK
| | - Christine Riches
- Department of Medicine and Wellcome Trust/MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Nicholas Heeley
- Department of Medicine and Wellcome Trust/MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Yue Ruan
- Department of Medicine and Wellcome Trust/MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Marcelo Rubinstein
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Consejo Nacional de Investigaciones Científicas y Técnicas, 1428 Buenos Aires, Argentina
| | - Malcolm J Low
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Martin G Myers
- Division of Metabolism, Endocrinology, and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | | | - Mark L Evans
- Department of Medicine and Wellcome Trust/MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK.
| | - Lora K Heisler
- Department of Pharmacology, University of Cambridge, Cambridge, UK; The Rowett Institute, University of Aberdeen, Aberdeen, UK.
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