1
|
Gaspari S, Labouèbe G, Picard A, Berney X, Rodriguez Sanchez‐Archidona A, Thorens B. Tmem117 in AVP neurons regulates the counterregulatory response to hypoglycemia. EMBO Rep 2023; 24:e57344. [PMID: 37314252 PMCID: PMC10398655 DOI: 10.15252/embr.202357344] [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: 04/14/2023] [Revised: 05/21/2023] [Accepted: 05/31/2023] [Indexed: 06/15/2023] Open
Abstract
The counterregulatory response to hypoglycemia (CRR), which ensures a sufficient glucose supply to the brain, is an essential survival function. It is orchestrated by incompletely characterized glucose-sensing neurons, which trigger a coordinated autonomous and hormonal response that restores normoglycemia. Here, we investigate the role of hypothalamic Tmem117, identified in a genetic screen as a regulator of CRR. We show that Tmem117 is expressed in vasopressin magnocellular neurons of the hypothalamus. Tmem117 inactivation in these neurons increases hypoglycemia-induced vasopressin secretion leading to higher glucagon secretion in male mice, and this effect is estrus cycle phase dependent in female mice. Ex vivo electrophysiological analysis, in situ hybridization, and in vivo calcium imaging reveal that Tmem117 inactivation does not affect the glucose-sensing properties of vasopressin neurons but increases ER stress, ROS production, and intracellular calcium levels accompanied by increased vasopressin production and secretion. Thus, Tmem117 in vasopressin neurons is a physiological regulator of glucagon secretion, which highlights the role of these neurons in the coordinated response to hypoglycemia.
Collapse
Affiliation(s)
- Sevasti Gaspari
- Center for Integrative GenomicsUniversity of LausanneLausanneSwitzerland
| | - Gwenaël Labouèbe
- Center for Integrative GenomicsUniversity of LausanneLausanneSwitzerland
| | - Alexandre Picard
- Center for Integrative GenomicsUniversity of LausanneLausanneSwitzerland
| | - Xavier Berney
- Center for Integrative GenomicsUniversity of LausanneLausanneSwitzerland
| | | | - Bernard Thorens
- Center for Integrative GenomicsUniversity of LausanneLausanneSwitzerland
| |
Collapse
|
2
|
Barahona MJ, Langlet F, Labouèbe G, Croizier S, Picard A, Thorens B, García-Robles MA. GLUT2 expression by glial fibrillary acidic protein-positive tanycytes is required for promoting feeding-response to fasting. Sci Rep 2022; 12:17717. [PMID: 36271117 PMCID: PMC9587252 DOI: 10.1038/s41598-022-22489-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 10/14/2022] [Indexed: 01/18/2023] Open
Abstract
Feeding behavior is a complex process that depends on the ability of the brain to integrate hormonal and nutritional signals, such as glucose. One glucosensing mechanism relies on the glucose transporter 2 (GLUT2) in the hypothalamus, especially in radial glia-like cells called tanycytes. Here, we analyzed whether a GLUT2-dependent glucosensing mechanism is required for the normal regulation of feeding behavior in GFAP-positive tanycytes. Genetic inactivation of Glut2 in GFAP-expressing tanycytes was performed using Cre/Lox technology. The efficiency of GFAP-tanycyte targeting was analyzed in the anteroposterior and dorsoventral axes by evaluating GFP fluorescence. Feeding behavior, hormonal levels, neuronal activity using c-Fos, and neuropeptide expression were also analyzed in the fasting-to-refeeding transition. In basal conditions, Glut2-inactivated mice had normal food intake and meal patterns. Implementation of a preceeding fasting period led to decreased total food intake and a delay in meal initiation during refeeding. Additionally, Glut2 inactivation increased the number of c-Fos-positive cells in the ventromedial nucleus in response to fasting and a deregulation of Pomc expression in the fasting-to-refeeding transition. Thus, a GLUT2-dependent glucose-sensing mechanism in GFAP-tanycytes is required to control food consumption and promote meal initiation after a fasting period.
Collapse
Affiliation(s)
- M. J. Barahona
- grid.5380.e0000 0001 2298 9663Laboratorio de Biología Celular, Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile ,grid.5380.e0000 0001 2298 9663Present Address: Laboratorio de Neurobiología y células madres (NeuroCellT), Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - F. Langlet
- grid.9851.50000 0001 2165 4204Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland ,grid.9851.50000 0001 2165 4204Present Address: Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - G. Labouèbe
- grid.9851.50000 0001 2165 4204Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - S. Croizier
- grid.9851.50000 0001 2165 4204Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - A. Picard
- grid.9851.50000 0001 2165 4204Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Bernard Thorens
- grid.9851.50000 0001 2165 4204Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - María A. García-Robles
- grid.5380.e0000 0001 2298 9663Laboratorio de Biología Celular, Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile ,grid.412185.b0000 0000 8912 4050Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, Valparaiso, Chile
| |
Collapse
|
3
|
Lipid biosynthesis enzyme Agpat5 in AgRP-neurons is required for insulin-induced hypoglycemia sensing and glucagon secretion. Nat Commun 2022; 13:5761. [PMID: 36180454 PMCID: PMC9525695 DOI: 10.1038/s41467-022-33484-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 09/21/2022] [Indexed: 11/13/2022] Open
Abstract
The counterregulatory response to hypoglycemia that restores normal blood glucose levels is an essential physiological function. It is initiated, in large part, by incompletely characterized brain hypoglycemia sensing neurons that trigger the secretion of counterregulatory hormones, in particular glucagon, to stimulate hepatic glucose production. In a genetic screen of recombinant inbred BXD mice we previously identified Agpat5 as a candidate regulator of hypoglycemia-induced glucagon secretion. Here, using genetic mouse models, we demonstrate that Agpat5 expressed in agouti-related peptide neurons is required for their activation by hypoglycemia, for hypoglycemia-induced vagal nerve activity, and glucagon secretion. We find that inactivation of Agpat5 leads to increased fatty acid oxidation and ATP production and that suppressing Cpt1a-dependent fatty acid import into mitochondria restores hypoglycemia sensing. Collectively, our data show that AgRP neurons are involved in the control of glucagon secretion and that Agpat5, by partitioning fatty acyl-CoAs away from mitochondrial fatty acid oxidation and ATP generation, ensures that the fall in intracellular ATP, which triggers neuronal firing, faithfully reflects changes in glycemia. During hypoglycemia, glucagon secretion is part of the mechanism needed to restore normal blood glucose levels. Here, Strembitska et al. report that sensing of hypoglycemia by AgRP neurons requires Agpat5, an enzyme which prevents fatty acids from entering the mitochondria for ATP production, ensuring correct neuronal activation and glucagon secretion.
Collapse
|
4
|
Tu L, Fukuda M, Tong Q, Xu Y. The ventromedial hypothalamic nucleus: watchdog of whole-body glucose homeostasis. Cell Biosci 2022; 12:71. [PMID: 35619170 PMCID: PMC9134642 DOI: 10.1186/s13578-022-00799-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 04/25/2022] [Indexed: 02/06/2023] Open
Abstract
The brain, particularly the ventromedial hypothalamic nucleus (VMH), has been long known for its involvement in glucose sensing and whole-body glucose homeostasis. However, it is still not fully understood how the brain detects and responds to the changes in the circulating glucose levels, as well as brain-body coordinated control of glucose homeostasis. In this review, we address the growing evidence implicating the brain in glucose homeostasis, especially in the contexts of hypoglycemia and diabetes. In addition to neurons, we emphasize the potential roles played by non-neuronal cells, as well as extracellular matrix in the hypothalamus in whole-body glucose homeostasis. Further, we review the ionic mechanisms by which glucose-sensing neurons sense fluctuations of ambient glucose levels. We also introduce the significant implications of heterogeneous neurons in the VMH upon glucose sensing and whole-body glucose homeostasis, in which sex difference is also addressed. Meanwhile, research gaps have also been identified, which necessities further mechanistic studies in future.
Collapse
Affiliation(s)
- Longlong Tu
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, 1100 Bates Street #8066, Houston, TX, 77030, USA
| | - Makoto Fukuda
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, 1100 Bates Street #8066, Houston, TX, 77030, USA
| | - Qingchun Tong
- Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Yong Xu
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, 1100 Bates Street #8066, Houston, TX, 77030, USA.
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA.
| |
Collapse
|
5
|
Picard A, Berney X, Castillo-Armengol J, Tarussio D, Jan M, Sanchez-Archidona AR, Croizier S, Thorens B. Hypothalamic Irak4 is a genetically-controlled regulator of hypoglycemia-induced glucagon secretion. Mol Metab 2022; 61:101479. [PMID: 35339728 PMCID: PMC9046887 DOI: 10.1016/j.molmet.2022.101479] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/16/2022] [Accepted: 03/17/2022] [Indexed: 11/26/2022] Open
Abstract
OBJECTIVES Glucagon secretion to stimulate hepatic glucose production is a first line of defense against hypoglycemia. This response is triggered by so far incompletely characterized central hypoglycemia sensing mechanisms, which control autonomous nervous activity and hormone secretion. The objective of this study was to identify novel hypothalamic genes controlling insulin-induced glucagon secretion. METHODS To obtain new information about the mechanisms of hypothalamic hypoglycemia sensing, we combined genetic and transcriptomic analysis of the glucagon response to insulin-induced hypoglycemia in a panel of BXD recombinant inbred mice. RESULTS We identified two QTLs, on chromosome 8 and chromosome 15. We further investigated the role of Irak4 and Cpne8, both located in the chromosome 15 QTL, in C57BL/6J and DBA/2J mice, the BXD mouse parental strains. We found that the poor glucagon response of DBA/2J mice was associated with higher hypothalamic expression of Irak4, which encodes a kinase acting downstream of the interleukin-1 receptor (Il-1R), and of Il-ß when compared to C57BL/6J mice. We showed that intracerebroventricular administration of an Il-1R antagonist in DBA/2J restored insulin-induced glucagon secretion; this was associated with increased c-fos expression in the arcuate and paraventricular nuclei of the hypothalamus and with higher activation of both branches of the autonomous nervous system. Whole body inactivation of Cpne8, which encodes a Ca++-dependent regulator of membrane trafficking and exocytosis had, however, no impact on insulin-induced glucagon secretion. CONCLUSIONS Collectively, our data identify Irak4 as a genetically controlled regulator of hypoglycemia-activated hypothalamic neurons and glucagon secretion.
Collapse
Affiliation(s)
- Alexandre Picard
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Xavier Berney
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Judit Castillo-Armengol
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland; Novo Nordisk A/S, Måløv, Denmark
| | - David Tarussio
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Maxime Jan
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | | | - Sophie Croizier
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
| |
Collapse
|
6
|
Thorens B. Neuronal regulation of glucagon secretion and gluconeogenesis. J Diabetes Investig 2022; 13:599-607. [PMID: 34989155 PMCID: PMC9017634 DOI: 10.1111/jdi.13745] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 01/02/2022] [Indexed: 11/29/2022] Open
Abstract
Hypoglycemia almost never develops in healthy individuals because multiple hypoglycemia sensing systems, located in the periphery and in the central nervous system trigger a coordinated counterregulatory hormonal response to restore normoglycemia. This involves not only the secretion of glucagon but also of epinephrine, norepinephrine, cortisol and growth hormone. Increased hepatic glucose production is also stimulated by direct autonomous nervous connections to the liver that stimulate glycogenolysis and gluconeogenesis. This counterregulatory response, however, becomes deregulated in a significant fraction of diabetic patients that receive insulin therapy. This leads to risk of developing hypoglycemic episodes, of increasing severity, which negatively impact the quality of life of the patients. How hypoglycemia is detected by the central nervous system is being actively investigated. Recent studies using novel molecular biological, optogenetic and chemogenetic techniques, allow the characterization of glucose sensing neurons, the mechanisms of hypoglycemia detection, the neuronal circuits in which they are integrated and the physiological responses they control. This review will discuss recent studies aimed at identifying central hypoglycemia sensing neuronal circuits, how neurons are activated by hypoglycemia, and how they restore normoglycemia.
Collapse
Affiliation(s)
- Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, 1015, Lausanne, Switzerland
| |
Collapse
|
7
|
Torres Irizarry VC, Jiang Y, He Y, Xu P. Hypothalamic Estrogen Signaling and Adipose Tissue Metabolism in Energy Homeostasis. Front Endocrinol (Lausanne) 2022; 13:898139. [PMID: 35757435 PMCID: PMC9218066 DOI: 10.3389/fendo.2022.898139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 04/29/2022] [Indexed: 11/30/2022] Open
Abstract
Obesity has become a global epidemic, and it is a major risk factor for other metabolic disorders such as type 2 diabetes and cardiometabolic disease. Accumulating evidence indicates that there is sex-specific metabolic protection and disease susceptibility. For instance, in both clinical and experimental studies, males are more likely to develop obesity, insulin resistance, and diabetes. In line with this, males tend to have more visceral white adipose tissue (WAT) and less brown adipose tissue (BAT) thermogenic activity, both leading to an increased incidence of metabolic disorders. This female-specific fat distribution is partially mediated by sex hormone estrogens. Specifically, hypothalamic estrogen signaling plays a vital role in regulating WAT distribution, WAT beiging, and BAT thermogenesis. These regulatory effects on adipose tissue metabolism are primarily mediated by the activation of estrogen receptor alpha (ERα) in neurons, which interacts with hormones and adipokines such as leptin, ghrelin, and insulin. This review discusses the contribution of adipose tissue dysfunction to obesity and the role of hypothalamic estrogen signaling in preventing metabolic diseases with a particular focus on the VMH, the central regulator of energy expenditure and glucose homeostasis.
Collapse
Affiliation(s)
- Valeria C. Torres Irizarry
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, The University of Illinois at Chicago, Chicago, IL, United States
- Department of Physiology and Biophysics, The University of Illinois at Chicago, Chicago, IL, United States
| | - Yuwei Jiang
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, The University of Illinois at Chicago, Chicago, IL, United States
- Department of Physiology and Biophysics, The University of Illinois at Chicago, Chicago, IL, United States
- *Correspondence: Yuwei Jiang, ; Yanlin He, ; Pingwen Xu,
| | - Yanlin He
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA, United States
- *Correspondence: Yuwei Jiang, ; Yanlin He, ; Pingwen Xu,
| | - Pingwen Xu
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, The University of Illinois at Chicago, Chicago, IL, United States
- Department of Physiology and Biophysics, The University of Illinois at Chicago, Chicago, IL, United States
- *Correspondence: Yuwei Jiang, ; Yanlin He, ; Pingwen Xu,
| |
Collapse
|
8
|
Kessler S, Labouèbe G, Croizier S, Gaspari S, Tarussio D, Thorens B. Glucokinase neurons of the paraventricular nucleus of the thalamus sense glucose and decrease food consumption. iScience 2021; 24:103122. [PMID: 34622169 PMCID: PMC8481977 DOI: 10.1016/j.isci.2021.103122] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/08/2021] [Accepted: 09/09/2021] [Indexed: 12/27/2022] Open
Abstract
The paraventricular nucleus of the thalamus (PVT) controls goal-oriented behavior through its connections to the nucleus accumbens (NAc). We previously characterized Glut2aPVT neurons that are activated by hypoglycemia, and which increase sucrose seeking behavior through their glutamatergic projections to the NAc. Here, we identified glucokinase (Gck)-expressing neurons of the PVT (GckaPVT) and generated a mouse line expressing the Cre recombinase from the glucokinase locus (Gck Cre/+ mice). Ex vivo calcium imaging and whole-cell patch clamp recordings revealed that GckaPVT neurons that project to the NAc were mostly activated by hyperglycemia. Their chemogenetic inhibition or optogenetic stimulation, respectively, enhanced food intake or decreased sucrose-seeking behavior. Collectively, our results describe a neuronal population of Gck-expressing neurons in the PVT, which has opposite glucose sensing properties and control over feeding behavior than the previously characterized Glut2aPVT neurons. This study allows a better understanding of the complex regulation of feeding behavior by the PVT.
Collapse
Affiliation(s)
- Sébastien Kessler
- Center for Integrative Genomics, University of Lausanne, Genopode Building, 1015 Lausanne, Switzerland
| | - Gwenaël Labouèbe
- Center for Integrative Genomics, University of Lausanne, Genopode Building, 1015 Lausanne, Switzerland
| | - Sophie Croizier
- Center for Integrative Genomics, University of Lausanne, Genopode Building, 1015 Lausanne, Switzerland
| | - Sevasti Gaspari
- Center for Integrative Genomics, University of Lausanne, Genopode Building, 1015 Lausanne, Switzerland
| | - David Tarussio
- Center for Integrative Genomics, University of Lausanne, Genopode Building, 1015 Lausanne, Switzerland
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, Genopode Building, 1015 Lausanne, Switzerland
| |
Collapse
|
9
|
Rohrbach A, Caron E, Dali R, Brunner M, Pasquettaz R, Kolotuev I, Santoni F, Thorens B, Langlet F. Ablation of glucokinase-expressing tanycytes impacts energy balance and increases adiposity in mice. Mol Metab 2021; 53:101311. [PMID: 34325016 PMCID: PMC8379510 DOI: 10.1016/j.molmet.2021.101311] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 07/20/2021] [Indexed: 01/06/2023] Open
Abstract
Objectives Glucokinase (GCK) is critical for glucosensing. In rats, GCK is expressed in hypothalamic tanycytes and appears to play an essential role in feeding behavior. In this study, we investigated the distribution of GCK-expressing tanycytes in mice and their role in the regulation of energy balance. Methods In situ hybridization, reporter gene assay, and immunohistochemistry were used to assess GCK expression along the third ventricle in mice. To evaluate the impact of GCK-expressing tanycytes on arcuate neuron function and mouse physiology, Gck deletion along the ventricle was achieved using loxP/Cre recombinase technology in adult mice. Results GCK expression was low along the third ventricle, but detectable in tanycytes facing the ventromedial arcuate nucleus from bregma −1.5 to −2.2. Gck deletion induced the death of this tanycyte subgroup through the activation of the BAD signaling pathway. The ablation of GCK-expressing tanycytes affected different aspects of energy balance, leading to an increase in adiposity in mice. This phenotype was systematically associated with a defect in NPY neuron function. In contrast, the regulation of glucose homeostasis was mostly preserved, except for glucoprivic responses. Conclusions This study describes the role of GCK in tanycyte biology and highlights the impact of tanycyte loss on the regulation of energy balance. vmARH tanycytes express glucokinase. Glucokinase deletion in tanycytes induces cell death. Ablation of vmARH tanycytes alters energy balance and adiposity. Ablation of vmARH tanycytes alters NPY neuron function.
Collapse
Affiliation(s)
- Antoine Rohrbach
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland; Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Emilie Caron
- Univ. Lille, Inserm, CHU Lille, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Lille Neuroscience & Cognition, UMR-S, 1172, Lille, France
| | - Rafik Dali
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Maxime Brunner
- Service of Endocrinology, Diabetology, and Metabolism, Lausanne University Hospital, Faculty of Biology and Medicine, 1011, Lausanne, Switzerland
| | - Roxane Pasquettaz
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Irina Kolotuev
- Electron Microscopy Facility, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Federico Santoni
- Service of Endocrinology, Diabetology, and Metabolism, Lausanne University Hospital, Faculty of Biology and Medicine, 1011, Lausanne, Switzerland
| | - Bernard Thorens
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Fanny Langlet
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland; Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland.
| |
Collapse
|
10
|
Picard A, Metref S, Tarussio D, Dolci W, Berney X, Croizier S, Labouebe G, Thorens B. Fgf15 Neurons of the Dorsomedial Hypothalamus Control Glucagon Secretion and Hepatic Gluconeogenesis. Diabetes 2021; 70:1443-1457. [PMID: 33883213 PMCID: PMC8336003 DOI: 10.2337/db20-1121] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 04/03/2021] [Indexed: 11/18/2022]
Abstract
The counterregulatory response to hypoglycemia is an essential survival function. It is controlled by an integrated network of glucose-responsive neurons, which trigger endogenous glucose production to restore normoglycemia. The complexity of this glucoregulatory network is, however, only partly characterized. In a genetic screen of a panel of recombinant inbred mice we previously identified Fgf15, expressed in neurons of the dorsomedial hypothalamus (DMH), as a negative regulator of glucagon secretion. Here, we report on the generation of Fgf15CretdTomato mice and their use to further characterize these neurons. We show that they were glutamatergic and comprised glucose-inhibited and glucose-excited neurons. When activated by chemogenetics, Fgf15 neurons prevented the increase in vagal nerve firing and the secretion of glucagon normally triggered by insulin-induced hypoglycemia. On the other hand, they increased the activity of the sympathetic nerve in the basal state and prevented its silencing by glucose overload. Higher sympathetic tone increased hepatic Creb1 phosphorylation, Pck1 mRNA expression, and hepatic glucose production leading to glucose intolerance. Thus, Fgf15 neurons of the DMH participate in the counterregulatory response to hypoglycemia by a direct adrenergic stimulation of hepatic glucose production while suppressing vagally induced glucagon secretion. This study provides new insights into the complex neuronal network that prevents the development of hypoglycemia.
Collapse
Affiliation(s)
- Alexandre Picard
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Salima Metref
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - David Tarussio
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Wanda Dolci
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Xavier Berney
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Sophie Croizier
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Gwenaël Labouebe
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| |
Collapse
|
11
|
He Y, Xu P, Wang C, Xia Y, Yu M, Yang Y, Yu K, Cai X, Qu N, Saito K, Wang J, Hyseni I, Robertson M, Piyarathna B, Gao M, Khan SA, Liu F, Chen R, Coarfa C, Zhao Z, Tong Q, Sun Z, Xu Y. Estrogen receptor-α expressing neurons in the ventrolateral VMH regulate glucose balance. Nat Commun 2020; 11:2165. [PMID: 32358493 PMCID: PMC7195451 DOI: 10.1038/s41467-020-15982-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 04/06/2020] [Indexed: 12/20/2022] Open
Abstract
Brain glucose-sensing neurons detect glucose fluctuations and prevent severe hypoglycemia, but mechanisms mediating functions of these glucose-sensing neurons are unclear. Here we report that estrogen receptor-α (ERα)-expressing neurons in the ventrolateral subdivision of the ventromedial hypothalamic nucleus (vlVMH) can sense glucose fluctuations, being glucose-inhibited neurons (GI-ERαvlVMH) or glucose-excited neurons (GE-ERαvlVMH). Hypoglycemia activates GI-ERαvlVMH neurons via the anoctamin 4 channel, and inhibits GE-ERαvlVMH neurons through opening the ATP-sensitive potassium channel. Further, we show that GI-ERαvlVMH neurons preferentially project to the medioposterior arcuate nucleus of the hypothalamus (mpARH) and GE-ERαvlVMH neurons preferentially project to the dorsal Raphe nuclei (DRN). Activation of ERαvlVMH to mpARH circuit and inhibition of ERαvlVMH to DRN circuit both increase blood glucose. Thus, our results indicate that ERαvlVMH neurons detect glucose fluctuations and prevent severe hypoglycemia in mice.
Collapse
Affiliation(s)
- Yanlin He
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Pingwen Xu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Chunmei Wang
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Yan Xia
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Meng Yu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Yongjie Yang
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Kaifan Yu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Xing Cai
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Na Qu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Kenji Saito
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Julia Wang
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Ilirjana Hyseni
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Matthew Robertson
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Badrajee Piyarathna
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Min Gao
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Sohaib A Khan
- Department of Cell and Cancer Biology, Vontz Center for Molecular Studies, University of Cincinnati, College of Medicine, Cincinnati, OH, 45267, USA
| | - Feng Liu
- Departments of Pharmacology, University of Texas Health at San Antonio, San Antonio, TX, 78229, USA
| | - Rui Chen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Cristian Coarfa
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Zhongming Zhao
- Center for Precision Health, School of Biomedical Informatics, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Qingchun Tong
- Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Zheng Sun
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
- Department of Medicine, Division of Diabetes, Endocrinology and Metabolism, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Yong Xu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA.
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA.
| |
Collapse
|
12
|
Deol P, Kozlova E, Valdez M, Ho C, Yang EW, Richardson H, Gonzalez G, Truong E, Reid J, Valdez J, Deans JR, Martinez-Lomeli J, Evans JR, Jiang T, Sladek FM, Curras-Collazo MC. Dysregulation of Hypothalamic Gene Expression and the Oxytocinergic System by Soybean Oil Diets in Male Mice. Endocrinology 2020; 161:5698148. [PMID: 31912136 PMCID: PMC7041656 DOI: 10.1210/endocr/bqz044] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 01/04/2020] [Indexed: 01/04/2023]
Abstract
Soybean oil consumption has increased greatly in the past half-century and is linked to obesity and diabetes. To test the hypothesis that soybean oil diet alters hypothalamic gene expression in conjunction with metabolic phenotype, we performed RNA sequencing analysis using male mice fed isocaloric, high-fat diets based on conventional soybean oil (high in linoleic acid, LA), a genetically modified, low-LA soybean oil (Plenish), and coconut oil (high in saturated fat, containing no LA). The 2 soybean oil diets had similar but nonidentical effects on the hypothalamic transcriptome, whereas the coconut oil diet had a negligible effect compared to a low-fat control diet. Dysregulated genes were associated with inflammation, neuroendocrine, neurochemical, and insulin signaling. Oxt was the only gene with metabolic, inflammation, and neurological relevance upregulated by both soybean oil diets compared to both control diets. Oxytocin immunoreactivity in the supraoptic and paraventricular nuclei of the hypothalamus was reduced, whereas plasma oxytocin and hypothalamic Oxt were increased. These central and peripheral effects of soybean oil diets were correlated with glucose intolerance but not body weight. Alterations in hypothalamic Oxt and plasma oxytocin were not observed in the coconut oil diet enriched in stigmasterol, a phytosterol found in soybean oil. We postulate that neither stigmasterol nor LA is responsible for effects of soybean oil diets on oxytocin and that Oxt messenger RNA levels could be associated with the diabetic state. Given the ubiquitous presence of soybean oil in the American diet, its observed effects on hypothalamic gene expression could have important public health ramifications.
Collapse
Affiliation(s)
- Poonamjot Deol
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, California
| | - Elena Kozlova
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, California
- Neuroscience Graduate Program, University of California, Riverside, California
| | - Matthew Valdez
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, California
- Neuroscience Graduate Program, University of California, Riverside, California
| | - Catherine Ho
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, California
| | - Ei-Wen Yang
- Department of Computer Science and Engineering, University of California Riverside, California
| | - Holly Richardson
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, California
| | - Gwendolyn Gonzalez
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, California
| | - Edward Truong
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, California
| | - Jack Reid
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, California
| | - Joseph Valdez
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, California
| | - Jonathan R Deans
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, California
| | - Jose Martinez-Lomeli
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, California
| | - Jane R Evans
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, California
| | - Tao Jiang
- Department of Computer Science and Engineering, University of California Riverside, California
| | - Frances M Sladek
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, California
| | - Margarita C Curras-Collazo
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, California
- Neuroscience Graduate Program, University of California, Riverside, California
- Correspondence: Margarita C. Curras-Collazo, PhD, FAPS, Department of Molecular, Cell and Systems Biology, University of California, 2110 Biological Sciences Building, Riverside, California 92521. E-mail:
| |
Collapse
|
13
|
Kammel LG, Correa SM. Selective sexual differentiation of neurone populations may contribute to sex-specific outputs of the ventromedial nucleus of the hypothalamus. J Neuroendocrinol 2020; 32:e12801. [PMID: 31605642 PMCID: PMC6982598 DOI: 10.1111/jne.12801] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 09/26/2019] [Accepted: 10/08/2019] [Indexed: 12/11/2022]
Abstract
Sex differences among neurones in the ventrolateral region of the ventromedial hypothalamic nucleus (VMHvl) allow for the display of a diversity of sex-typical behaviours and physiological responses, ranging from mating behaviour to metabolism. Here, we review recent studies that interrogate the relationship between sex-typical responses and changes in cellular phenotypes. We discuss technologies that increase the resolution of molecular profiling or targeting of cell populations, including single-cell transcriptional profiling and conditional viral genetic approaches to manipulate neurone survival or activity. Overall, emerging studies indicate that sex-typical functions of the VMH may be mediated by phenotypically distinct and sexually differentiated neurone populations within the VMHvl. Future studies in this and other brain regions could exploit cell-type-specific tools to reveal the cell populations and molecular mediators that modulate sex-typical responses. Furthermore, cell-type-specific analyses of the effects of sexually differentiating factors, including sex hormones, can test the hypothesis that distinct cell types within a single brain region vary with respect to sexual differentiation.
Collapse
Affiliation(s)
- Laura G Kammel
- Department of Integrative Biology and Physiology, Laboratory of Neuroendocrinology of the Brain Research Institute, University of California, Los Angeles, CA, USA
- Molecular, Cellular, Integrative Physiology Graduate Program, University of California, Los Angeles, CA, USA
| | - Stephanie M Correa
- Department of Integrative Biology and Physiology, Laboratory of Neuroendocrinology of the Brain Research Institute, University of California, Los Angeles, CA, USA
| |
Collapse
|
14
|
Stanley S, Moheet A, Seaquist ER. Central Mechanisms of Glucose Sensing and Counterregulation in Defense of Hypoglycemia. Endocr Rev 2019; 40:768-788. [PMID: 30689785 PMCID: PMC6505456 DOI: 10.1210/er.2018-00226] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 01/17/2019] [Indexed: 12/12/2022]
Abstract
Glucose homeostasis requires an organism to rapidly respond to changes in plasma glucose concentrations. Iatrogenic hypoglycemia as a result of treatment with insulin or sulfonylureas is the most common cause of hypoglycemia in humans and is generally only seen in patients with diabetes who take these medications. The first response to a fall in glucose is the detection of impending hypoglycemia by hypoglycemia-detecting sensors, including glucose-sensing neurons in the hypothalamus and other regions. This detection is then linked to a series of neural and hormonal responses that serve to prevent the fall in blood glucose and restore euglycemia. In this review, we discuss the current state of knowledge about central glucose sensing and how detection of a fall in glucose leads to the stimulation of counterregulatory hormone and behavior responses. We also review how diabetes and recurrent hypoglycemia impact glucose sensing and counterregulation, leading to development of impaired awareness of hypoglycemia in diabetes.
Collapse
Affiliation(s)
- Sarah Stanley
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Amir Moheet
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Elizabeth R Seaquist
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| |
Collapse
|
15
|
Matschinsky FM, Wilson DF. The Central Role of Glucokinase in Glucose Homeostasis: A Perspective 50 Years After Demonstrating the Presence of the Enzyme in Islets of Langerhans. Front Physiol 2019; 10:148. [PMID: 30949058 PMCID: PMC6435959 DOI: 10.3389/fphys.2019.00148] [Citation(s) in RCA: 152] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 02/07/2019] [Indexed: 01/05/2023] Open
Abstract
It is hypothesized that glucokinase (GCK) is the glucose sensor not only for regulation of insulin release by pancreatic β-cells, but also for the rest of the cells that contribute to glucose homeostasis in mammals. This includes other cells in endocrine pancreas (α- and δ-cells), adrenal gland, glucose sensitive neurons, entero-endocrine cells, and cells in the anterior pituitary. Glucose transport is by facilitated diffusion and is not rate limiting. Once inside, glucose is phosphorylated to glucose-6-phosphate by GCK in a reaction that is dependent on glucose throughout the physiological range of concentrations, is irreversible, and not product inhibited. High glycerol phosphate shuttle, pyruvate dehydrogenase, and pyruvate carboxylase activities, combined with low pentose-P shunt, lactate dehydrogenase, plasma membrane monocarboxylate transport, and glycogen synthase activities constrain glucose-6-phosphate to being metabolized through glycolysis. Under these conditions, glycolysis produces mostly pyruvate and little lactate. Pyruvate either enters the citric acid cycle through pyruvate dehydrogenase or is carboxylated by pyruvate carboxylase. Reducing equivalents from glycolysis enter oxidative phosphorylation through both the glycerol phosphate shuttle and citric acid cycle. Raising glucose concentration increases intramitochondrial [NADH]/[NAD+] and thereby the energy state ([ATP]/[ADP][Pi]), decreasing [Mg2+ADP] and [AMP]. [Mg2+ADP] acts through control of KATP channel conductance, whereas [AMP] acts through regulation of AMP-dependent protein kinase. Specific roles of different cell types are determined by the diverse molecular mechanisms used to couple energy state to cell specific responses. Having a common glucose sensor couples complementary regulatory mechanisms into a tightly regulated and stable glucose homeostatic network.
Collapse
Affiliation(s)
- Franz M Matschinsky
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - David F Wilson
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| |
Collapse
|
16
|
Chakera AJ, Hurst PS, Spyer G, Ogunnowo-Bada EO, Marsh WJ, Riches CH, Yueh CY, Markkula SP, Dalley JW, Cox RD, Macdonald IA, Amiel SA, MacLeod KM, Heisler LK, Hattersley AT, Evans ML. Molecular reductions in glucokinase activity increase counter-regulatory responses to hypoglycemia in mice and humans with diabetes. Mol Metab 2018; 17:17-27. [PMID: 30146176 PMCID: PMC6197723 DOI: 10.1016/j.molmet.2018.08.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 08/02/2018] [Indexed: 12/25/2022] Open
Abstract
OBJECTIVE Appropriate glucose levels are essential for survival; thus, the detection and correction of low blood glucose is of paramount importance. Hypoglycemia prompts an integrated response involving reduction in insulin release and secretion of key counter-regulatory hormones glucagon and epinephrine that together promote endogenous glucose production to restore normoglycemia. However, specifically how this response is orchestrated remains to be fully clarified. The low affinity hexokinase glucokinase is found in glucose-sensing cells involved in glucose homeostasis including pancreatic β-cells and in certain brain areas. Here, we aimed to examine the role of glucokinase in triggering counter-regulatory hormonal responses to hypoglycemia, hypothesizing that reduced glucokinase activity would lead to increased and/or earlier triggering of responses. METHODS Hyperinsulinemic glucose clamps were performed to examine counter-regulatory responses to controlled hypoglycemic challenges created in humans with monogenic diabetes resulting from heterozygous glucokinase mutations (GCK-MODY). To examine the relative importance of glucokinase in different sensing areas, we then examined responses to clamped hypoglycemia in mice with molecularly defined disruption of whole body and/or brain glucokinase. RESULTS GCK-MODY patients displayed increased and earlier glucagon responses during hypoglycemia compared with a group of glycemia-matched patients with type 2 diabetes. Consistent with this, glucagon responses to hypoglycemia were also increased in I366F mice with mutated glucokinase and in streptozotocin-treated β-cell ablated diabetic I366F mice. Glucagon responses were normal in conditional brain glucokinase-knockout mice, suggesting that glucagon release during hypoglycemia is controlled by glucokinase-mediated glucose sensing outside the brain but not in β-cells. For epinephrine, we found increased responses in GCK-MODY patients, in β-cell ablated diabetic I366F mice and in conditional (nestin lineage) brain glucokinase-knockout mice, supporting a role for brain glucokinase in triggering epinephrine release. CONCLUSIONS Our data suggest that glucokinase in brain and other non β-cell peripheral hypoglycemia sensors is important in glucose homeostasis, allowing the body to detect and respond to a falling blood glucose.
Collapse
Affiliation(s)
- Ali J Chakera
- Institute of Clinical and Biomedical Sciences, University of Exeter, United Kingdom
| | - Paul S Hurst
- Wellcome Trust/ MRC Institute of Metabolic Science and Department of Medicine, University of Cambridge, United Kingdom
| | - Gill Spyer
- Institute of Clinical and Biomedical Sciences, University of Exeter, United Kingdom
| | - Emmanuel O Ogunnowo-Bada
- Wellcome Trust/ MRC Institute of Metabolic Science and Department of Medicine, University of Cambridge, United Kingdom
| | - William J Marsh
- Wellcome Trust/ MRC Institute of Metabolic Science and Department of Medicine, University of Cambridge, United Kingdom
| | - Christine H Riches
- Wellcome Trust/ MRC Institute of Metabolic Science and Department of Medicine, University of Cambridge, United Kingdom
| | - Chen-Yu Yueh
- Wellcome Trust/ MRC Institute of Metabolic Science and Department of Medicine, University of Cambridge, United Kingdom
| | - S Pauliina Markkula
- Wellcome Trust/ MRC Institute of Metabolic Science and Department of Medicine, University of Cambridge, United Kingdom
| | - Jeffrey W Dalley
- Behavioural and Clinical Neuroscience Institute and Departments of Psychology and Psychiatry, University of Cambridge, United Kingdom
| | - Roger D Cox
- MRC Harwell Institute, Mammalian Genetics Unit, Harwell Oxford, United Kingdom
| | - Ian A Macdonald
- MRC-ARUK Centre for Musculoskeletal Ageing and NIHR Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust/ University of Nottingham, Nottingham, United Kingdom
| | - Stephanie A Amiel
- Division of Diabetes and Nutritional Sciences, King's College London, United Kingdom
| | - Kenneth M MacLeod
- Institute of Clinical and Biomedical Sciences, University of Exeter, United Kingdom
| | - Lora K Heisler
- Rowett Institute, University of Aberdeen, United Kingdom
| | - Andrew T Hattersley
- Institute of Clinical and Biomedical Sciences, University of Exeter, United Kingdom.
| | - Mark L Evans
- Wellcome Trust/ MRC Institute of Metabolic Science and Department of Medicine, University of Cambridge, United Kingdom.
| |
Collapse
|
17
|
Pozo M, Claret M. Hypothalamic Control of Systemic Glucose Homeostasis: The Pancreas Connection. Trends Endocrinol Metab 2018; 29:581-594. [PMID: 29866501 DOI: 10.1016/j.tem.2018.05.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 05/10/2018] [Accepted: 05/12/2018] [Indexed: 12/22/2022]
Abstract
Maintenance of glucose homeostasis is mandatory for organismal survival. It is accomplished by complex and coordinated interplay between glucose detection mechanisms and multiple effector systems. The brain, in particular homeostatic regions such as the hypothalamus, plays a crucial role in orchestrating such a highly integral response. We review here current understanding of how the hypothalamus senses glucose availability and participates in systemic glucose homeostasis. We provide an update of the relevant signaling pathways and neuronal subsets involved, as well as of the mechanisms modulating metabolic processes in peripheral tissues such as liver, skeletal muscle, fat, and especially the pancreas. We also discuss the relevance of these networks in human biology and prevalent metabolic conditions such as diabetes and obesity.
Collapse
Affiliation(s)
- Macarena Pozo
- Neuronal Control of Metabolism (NeuCoMe) Laboratory, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain
| | - Marc Claret
- Neuronal Control of Metabolism (NeuCoMe) Laboratory, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain; Centro de Investigación Biomédica en Red (CIBER) de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 08036 Barcelona, Spain.
| |
Collapse
|
18
|
Basco D, Zhang Q, Salehi A, Tarasov A, Dolci W, Herrera P, Spiliotis I, Berney X, Tarussio D, Rorsman P, Thorens B. α-cell glucokinase suppresses glucose-regulated glucagon secretion. Nat Commun 2018; 9:546. [PMID: 29416045 PMCID: PMC5803227 DOI: 10.1038/s41467-018-03034-0] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 01/15/2018] [Indexed: 02/08/2023] Open
Abstract
Glucagon secretion by pancreatic α-cells is triggered by hypoglycemia and suppressed by high glucose levels; impaired suppression of glucagon secretion is a hallmark of both type 1 and type 2 diabetes. Here, we show that α-cell glucokinase (Gck) plays a role in the control of glucagon secretion. Using mice with α-cell-specific inactivation of Gck (αGckKO mice), we find that glucokinase is required for the glucose-dependent increase in intracellular ATP/ADP ratio and the closure of KATP channels in α-cells and the suppression of glucagon secretion at euglycemic and hyperglycemic levels. αGckKO mice display hyperglucagonemia in the fed state, which is associated with increased hepatic gluconeogenic gene expression and hepatic glucose output capacity. In adult mice, fed hyperglucagonemia is further increased and glucose intolerance develops. Thus, glucokinase governs an α-cell metabolic pathway that suppresses secretion at or above normoglycemic levels; abnormal suppression of glucagon secretion deregulates hepatic glucose metabolism and, over time, induces a pre-diabetic phenotype.
Collapse
Affiliation(s)
- Davide Basco
- Center for Integrative Genomics, University of Lausanne, 1015, Lausanne, Switzerland
| | - Quan Zhang
- Oxford Centre for Diabetes, Endocrinology, and Metabolism, University of Oxford, Churchill Hospital, Oxford, OX3 7LE, UK
| | - Albert Salehi
- Department of Clinical Science, UMAS, Division of Islet Cell Physiology, Lund, Sweden
| | - Andrei Tarasov
- Oxford Centre for Diabetes, Endocrinology, and Metabolism, University of Oxford, Churchill Hospital, Oxford, OX3 7LE, UK
| | - Wanda Dolci
- Center for Integrative Genomics, University of Lausanne, 1015, Lausanne, Switzerland
| | - Pedro Herrera
- Department of Genetic Medicine and Development, 1200, Geneva, Switzerland
| | - Ioannis Spiliotis
- Oxford Centre for Diabetes, Endocrinology, and Metabolism, University of Oxford, Churchill Hospital, Oxford, OX3 7LE, UK
| | - Xavier Berney
- Center for Integrative Genomics, University of Lausanne, 1015, Lausanne, Switzerland
| | - David Tarussio
- Center for Integrative Genomics, University of Lausanne, 1015, Lausanne, Switzerland
| | - Patrik Rorsman
- Oxford Centre for Diabetes, Endocrinology, and Metabolism, University of Oxford, Churchill Hospital, Oxford, OX3 7LE, UK
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, 1015, Lausanne, Switzerland.
| |
Collapse
|