1
|
Concetti C, Peleg-Raibstein D, Burdakov D. Hypothalamic MCH Neurons: From Feeding to Cognitive Control. FUNCTION 2023; 5:zqad059. [PMID: 38020069 PMCID: PMC10667013 DOI: 10.1093/function/zqad059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 10/06/2023] [Accepted: 10/11/2023] [Indexed: 12/01/2023] Open
Abstract
Modern neuroscience is progressively elucidating that the classic view positing distinct brain regions responsible for survival, emotion, and cognitive functions is outdated. The hypothalamus demonstrates the interdependence of these roles, as it is traditionally known for fundamental survival functions like energy and electrolyte balance, but is now recognized to also play a crucial role in emotional and cognitive processes. This review focuses on lateral hypothalamic melanin-concentrating hormone (MCH) neurons, producing the neuropeptide MCH-a relatively understudied neuronal population with integrative functions related to homeostatic regulation and motivated behaviors, with widespread inputs and outputs throughout the entire central nervous system. Here, we review early findings and recent literature outlining their role in the regulation of energy balance, sleep, learning, and memory processes.
Collapse
Affiliation(s)
- Cristina Concetti
- Neurobehavioural Dynamics Laboratory, ETH Zürich, Schorenstrasse 16, Schwerzenbach 8603, Switzerland
| | - Daria Peleg-Raibstein
- Neurobehavioural Dynamics Laboratory, ETH Zürich, Schorenstrasse 16, Schwerzenbach 8603, Switzerland
| | - Denis Burdakov
- Neurobehavioural Dynamics Laboratory, ETH Zürich, Schorenstrasse 16, Schwerzenbach 8603, Switzerland
| |
Collapse
|
2
|
Diedrich V, Haugg E, Van Hee J, Herwig A. Role of glucose in daily torpor of Djungarian hamsters ( Phodopus sungorus): challenge of continuous in vivo blood glucose measurements. Am J Physiol Regul Integr Comp Physiol 2023; 325:R359-R379. [PMID: 37519255 DOI: 10.1152/ajpregu.00040.2023] [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: 02/13/2023] [Revised: 07/03/2023] [Accepted: 07/23/2023] [Indexed: 08/01/2023]
Abstract
Djungarian hamsters use daily torpor to save energy during winter. This metabolic downstate is part of their acclimatization strategy in response to short photoperiod and expressed spontaneously without energy challenges. During acute energy shortage, torpor incidence, depth, and duration can be modulated. Torpor induction might rely on glucose availability as acute metabolic energy source. To investigate this, the present study provides the first continuous in vivo blood glucose measurements of spontaneous daily torpor in short photoperiod-acclimated and fasting-induced torpor in long photoperiod-acclimated Djungarian hamsters. Glucose levels were almost identical in both photoperiods and showed a decrease during resting phase. Further decreases appeared during spontaneous daily torpor entrance, parallel with metabolic rate but before body temperature, while respiratory exchange rates were rising. During arousal, blood glucose tended to increase, and pretorpor values were reached at torpor termination. Although food-restricted hamsters underwent a considerable energetic challenge, blood glucose levels remained stable during the resting phase regardless of torpor expression. The activity phase preceding a torpor bout did not reveal changes in blood glucose that might be used as torpor predictor. Djungarian hamsters show a robust, circadian rhythm in blood glucose irrespective of season and maintain appropriate levels throughout complex acclimation processes including metabolic downstates. Although these measurements could not reveal blood glucose as proximate torpor induction factor, they provide new information about glucose availability during torpor. Technical innovations like in vivo microdialysis and in vitro transcriptome or proteome analyses may help to uncover the connection between torpor expression and glucose metabolism.
Collapse
Affiliation(s)
| | - Elena Haugg
- Institute of Neurobiology, Ulm University, Ulm, Germany
| | - Justin Van Hee
- Data Sciences International, St. Paul, Minnesota, United States
| | - Annika Herwig
- Institute of Neurobiology, Ulm University, Ulm, Germany
| |
Collapse
|
3
|
Douglass JD, Ness KM, Valdearcos M, Wyse-Jackson A, Dorfman MD, Frey JM, Fasnacht RD, Santiago OD, Niraula A, Banerjee J, Robblee M, Koliwad SK, Thaler JP. Obesity-associated microglial inflammatory activation paradoxically improves glucose tolerance. Cell Metab 2023; 35:1613-1629.e8. [PMID: 37572666 PMCID: PMC10528677 DOI: 10.1016/j.cmet.2023.07.008] [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: 04/28/2022] [Revised: 06/09/2023] [Accepted: 07/19/2023] [Indexed: 08/14/2023]
Abstract
Hypothalamic gliosis associated with high-fat diet (HFD) feeding increases susceptibility to hyperphagia and weight gain. However, the body-weight-independent contribution of microglia to glucose regulation has not been determined. Here, we show that reducing microglial nuclear factor κB (NF-κB) signaling via cell-specific IKKβ deletion exacerbates HFD-induced glucose intolerance despite reducing body weight and adiposity. Conversely, two genetic approaches to increase microglial pro-inflammatory signaling (deletion of an NF-κB pathway inhibitor and chemogenetic activation through a modified Gq-coupled muscarinic receptor) improved glucose tolerance independently of diet in both lean and obese rodents. Microglial regulation of glucose homeostasis involves a tumor necrosis factor alpha (TNF-α)-dependent mechanism that increases activation of pro-opiomelanocortin (POMC) and other hypothalamic glucose-sensing neurons, ultimately leading to a marked amplification of first-phase insulin secretion via a parasympathetic pathway. Overall, these data indicate that microglia regulate glucose homeostasis in a body-weight-independent manner, an unexpected mechanism that limits the deterioration of glucose tolerance associated with obesity.
Collapse
Affiliation(s)
- John D Douglass
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA; Department of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Kelly M Ness
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA; Department of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Martin Valdearcos
- The Diabetes Center, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Alice Wyse-Jackson
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA; Department of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Mauricio D Dorfman
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA; Department of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Jeremy M Frey
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA; Department of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Rachael D Fasnacht
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA; Department of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Olivia D Santiago
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA; Department of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Anzela Niraula
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA; Department of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Jineta Banerjee
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA; Department of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Megan Robblee
- The Diabetes Center, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Suneil K Koliwad
- The Diabetes Center, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA.
| | - Joshua P Thaler
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA; Department of Medicine, University of Washington, Seattle, WA 98109, USA.
| |
Collapse
|
4
|
Makrygianni EA, Chrousos GP. Neural Progenitor Cells and the Hypothalamus. Cells 2023; 12:1822. [PMID: 37508487 PMCID: PMC10378393 DOI: 10.3390/cells12141822] [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: 03/02/2023] [Revised: 05/22/2023] [Accepted: 06/02/2023] [Indexed: 07/30/2023] Open
Abstract
Neural progenitor cells (NPCs) are multipotent neural stem cells (NSCs) capable of self-renewing and differentiating into neurons, astrocytes and oligodendrocytes. In the postnatal/adult brain, NPCs are primarily located in the subventricular zone (SVZ) of the lateral ventricles (LVs) and subgranular zone (SGZ) of the hippocampal dentate gyrus (DG). There is evidence that NPCs are also present in the postnatal/adult hypothalamus, a highly conserved brain region involved in the regulation of core homeostatic processes, such as feeding, metabolism, reproduction, neuroendocrine integration and autonomic output. In the rodent postnatal/adult hypothalamus, NPCs mainly comprise different subtypes of tanycytes lining the wall of the 3rd ventricle. In the postnatal/adult human hypothalamus, the neurogenic niche is constituted by tanycytes at the floor of the 3rd ventricle, ependymal cells and ribbon cells (showing a gap-and-ribbon organization similar to that in the SVZ), as well as suprachiasmatic cells. We speculate that in the postnatal/adult human hypothalamus, neurogenesis occurs in a highly complex, exquisitely sophisticated neurogenic niche consisting of at least four subniches; this structure has a key role in the regulation of extrahypothalamic neurogenesis, and hypothalamic and extrahypothalamic neural circuits, partly through the release of neurotransmitters, neuropeptides, extracellular vesicles (EVs) and non-coding RNAs (ncRNAs).
Collapse
Affiliation(s)
- Evanthia A Makrygianni
- University Research Institute of Maternal and Child Health & Precision Medicine, National and Kapodistrian University of Athens, 11527 Athens, Greece
| | - George P Chrousos
- University Research Institute of Maternal and Child Health & Precision Medicine, National and Kapodistrian University of Athens, 11527 Athens, Greece
| |
Collapse
|
5
|
Kannangara H, Cullen L, Miyashita S, Korkmaz F, Macdonald A, Gumerova A, Witztum R, Moldavski O, Sims S, Burgess J, Frolinger T, Latif R, Ginzburg Y, Lizneva D, Goosens K, Davies TF, Yuen T, Zaidi M, Ryu V. Emerging roles of brain tanycytes in regulating blood-hypothalamus barrier plasticity and energy homeostasis. Ann N Y Acad Sci 2023; 1525:61-69. [PMID: 37199228 PMCID: PMC10524199 DOI: 10.1111/nyas.15009] [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] [Indexed: 05/19/2023]
Abstract
Seasonal changes in food intake and adiposity in many animal species are triggered by changes in the photoperiod. These latter changes are faithfully transduced into a biochemical signal by melatonin secreted by the pineal gland. Seasonal variations, encoded by melatonin, are integrated by third ventricular tanycytes of the mediobasal hypothalamus through the detection of the thyroid-stimulating hormone (TSH) released from the pars tuberalis. The mediobasal hypothalamus is a critical brain region that maintains energy homeostasis by acting as an interface between the neural networks of the central nervous system and the periphery to control metabolic functions, including ingestive behavior, energy homeostasis, and reproduction. Among the cells involved in the regulation of energy balance and the blood-hypothalamus barrier (BHB) plasticity are tanycytes. Increasing evidence suggests that anterior pituitary hormones, specifically TSH, traditionally considered to have unitary functions in targeting single endocrine sites, display actions on multiple somatic tissues and central neurons. Notably, modulation of tanycytic TSH receptors seems critical for BHB plasticity in relation to energy homeostasis, but this needs to be proven.
Collapse
Affiliation(s)
- Hasni Kannangara
- Center for Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY
- Department of Medicine and of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Liam Cullen
- Center for Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY
- Department of Medicine and of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Sari Miyashita
- Center for Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY
- Department of Medicine and of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Funda Korkmaz
- Center for Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY
- Department of Medicine and of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Anne Macdonald
- Center for Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY
- Department of Medicine and of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Anisa Gumerova
- Center for Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY
- Department of Medicine and of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Ronit Witztum
- Center for Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY
- Department of Medicine and of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Ofer Moldavski
- Center for Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY
- Department of Medicine and of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Steven Sims
- Center for Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY
- Department of Medicine and of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Jocoll Burgess
- Center for Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY
- Department of Medicine and of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Tal Frolinger
- Center for Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY
- Department of Medicine and of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Rauf Latif
- Center for Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY
- Department of Medicine and of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Yelena Ginzburg
- Center for Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY
- Department of Medicine and of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Daria Lizneva
- Center for Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY
- Department of Medicine and of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Ki Goosens
- Center for Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Terry F. Davies
- Center for Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY
- Department of Medicine and of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Tony Yuen
- Center for Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY
- Department of Medicine and of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Mone Zaidi
- Center for Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY
- Department of Medicine and of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Vitaly Ryu
- Center for Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY
- Department of Medicine and of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| |
Collapse
|
6
|
Palani G, Stortz E, Moheet A. Clinical Presentation and Diagnostic Approach to Hypoglycemia in Adults Without Diabetes Mellitus. Endocr Pract 2023; 29:286-294. [PMID: 36464132 DOI: 10.1016/j.eprac.2022.11.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 10/24/2022] [Accepted: 11/28/2022] [Indexed: 12/03/2022]
Abstract
OBJECTIVE To review the clinical presentation, causes, and diagnostic approach to spontaneous hypoglycemia in adults without diabetes mellitus. METHODS A literature review was performed using the PubMed and Google Scholar databases. RESULTS Hypoglycemia is uncommon in people who are not on glucose-lowering medications. Under normal physiologic conditions, multiple neural and hormonal counterregulatory mechanisms prevent the development of abnormally low levels of plasma glucose. If spontaneous hypoglycemia is suspected, the Whipple triad should be used to confirm hypoglycemia before pursuing further diagnostic workup. The Whipple criteria include the following: (1) low levels of plasma glucose, (2) signs or symptoms that would be expected with low levels of plasma glucose, and (3) improvement in those signs or symptoms when the level of plasma glucose increases. Spontaneous hypoglycemia can be caused by conditions that cause endogenous hyperinsulinism, including insulinoma, postbariatric hypoglycemia, and noninsulinoma pancreatogenous hypoglycemia. Spontaneous hypoglycemia can also be seen with critical illness, hepatic or renal dysfunction, hormonal deficiency, non-diabetes-related medications, and non-islet cell tumors. The initial diagnostic approach should begin by obtaining a detailed history of the nature and timing of the patient's symptoms, medications, underlying comorbid conditions, and any acute illness. A laboratory evaluation should be conducted at the time of the spontaneous symptomatic episode. Supervised tests such as a 72-hour fast or mixed-meal test may be needed to recreate the situation under which the patient is likely to experience symptoms. CONCLUSION We provide an overview of the physiology of counterregulatory response to hypoglycemia, its causes, and diagnostic approaches to spontaneous hypoglycemia in adults.
Collapse
Affiliation(s)
- Gurunanthan Palani
- Division of Endocrinology and Diabetes, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Ethan Stortz
- Division of Endocrinology and Diabetes, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Amir Moheet
- Division of Endocrinology and Diabetes, Department of Medicine, University of Minnesota, Minneapolis, Minnesota.
| |
Collapse
|
7
|
Scariot PPM, Papoti M, Polisel EEC, Orsi JB, Van Ginkel PR, Prolla TA, Manchado-Gobatto FB, Gobatto CA. Living high - training low model applied to C57BL/6J mice: Effects on physiological parameters related to aerobic fitness and acid-base balance. Life Sci 2023; 317:121443. [PMID: 36709910 DOI: 10.1016/j.lfs.2023.121443] [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: 10/19/2022] [Revised: 01/17/2023] [Accepted: 01/23/2023] [Indexed: 01/27/2023]
Abstract
There is a scarcity of data regarding the acclimation to high altitude (hypoxic environment) accompanied by training at low altitude (normoxic conditions), the so-called "living high-training low" (LHTL) model in rodents. We aimed to investigate the effects of aerobic training on C57BL/6J mice living in normoxic (NOR) or hypoxic (HYP) environments on several parameters, including critical velocity (CV), a parameter regarded as a measure of aerobic capacity, on monocarboxylate transporters (MCTs) in muscles and hypothalamus, as well as on hematological parameters and body temperature. In each environment, mice were divided into non-trained (N) and trained (T). Forty rodents were distributed into the following experimental groups (N-NOR; T-NOR; N-HYP and T-HYP). HYP groups were in a normobaric tent where oxygen-depleted air was pumped from a hypoxia generator set an inspired oxygen fraction [FiO2] of 14.5 %. The HYP-groups were kept (18 h per day) in a normobaric tent for consecutive 8-weeks. Training sessions were conducted in normoxic conditions ([FiO2] = 19.5 %), 5 times per week (40 min per session) at intensity equivalent to 80 % of CV. In summary, eight weeks of LHTL did not promote a greater improvement in the CV, protein expression of MCTs in different tissues when compared to the application of training alone. The LHTL model increased red blood cells count, but reduced hemoglobin per erythrocyte was found in mice exposed to LHTL. Although the LHTL did not have a major effect on thermographic records, exercise-induced hyperthermia (in the head) was attenuated in HYP groups when compared to NOR groups.
Collapse
Affiliation(s)
- Pedro Paulo Menezes Scariot
- Laboratory of Applied Sport Physiology, School of Applied Sciences, University of Campinas, Limeira, SP, Brazil
| | - Marcelo Papoti
- School of Physical Education and Sport of Ribeirão Preto, University of São Paulo, SP, Brazil
| | | | - Juan Bordon Orsi
- Laboratory of Applied Sport Physiology, School of Applied Sciences, University of Campinas, Limeira, SP, Brazil
| | - Paul R Van Ginkel
- Department of Genetics & Medical Genetics, University of Wisconsin, Madison, WI, USA
| | - Tomas A Prolla
- Department of Genetics & Medical Genetics, University of Wisconsin, Madison, WI, USA
| | | | - Claudio Alexandre Gobatto
- Laboratory of Applied Sport Physiology, School of Applied Sciences, University of Campinas, Limeira, SP, Brazil.
| |
Collapse
|
8
|
Gala DS, Titlow JS, Teodoro RO, Davis I. Far from home: the role of glial mRNA localization in synaptic plasticity. RNA (NEW YORK, N.Y.) 2023; 29:153-169. [PMID: 36442969 PMCID: PMC9891262 DOI: 10.1261/rna.079422.122] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Neurons and glia are highly polarized cells, whose distal cytoplasmic functional subdomains require specific proteins. Neurons have axonal and dendritic cytoplasmic extensions containing synapses whose plasticity is regulated efficiently by mRNA transport and localized translation. The principles behind these mechanisms are equally attractive for explaining rapid local regulation of distal glial cytoplasmic projections, independent of their cell nucleus. However, in contrast to neurons, mRNA localization has received little experimental attention in glia. Nevertheless, there are many functionally diverse glial subtypes containing extensive networks of long cytoplasmic projections with likely localized regulation that influence neurons and their synapses. Moreover, glia have many other neuron-like properties, including electrical activity, secretion of gliotransmitters and calcium signaling, influencing, for example, synaptic transmission, plasticity and axon pruning. Here, we review previous studies concerning glial transcripts with important roles in influencing synaptic plasticity, focusing on a few cases involving localized translation. We discuss a variety of important questions about mRNA transport and localized translation in glia that remain to be addressed, using cutting-edge tools already available for neurons.
Collapse
Affiliation(s)
- Dalia S Gala
- Department of Biochemistry, The University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Joshua S Titlow
- Department of Biochemistry, The University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Rita O Teodoro
- iNOVA4Health, NOVA Medical School-Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa 1169-056, Portugal
| | - Ilan Davis
- Department of Biochemistry, The University of Oxford, Oxford OX1 3QU, United Kingdom
| |
Collapse
|
9
|
Hadjihambi A, Konstantinou C, Klohs J, Monsorno K, Le Guennec A, Donnelly C, Cox IJ, Kusumbe A, Hosford PS, Soffientini U, Lecca S, Mameli M, Jalan R, Paolicelli RC, Pellerin L. Partial MCT1 invalidation protects against diet-induced non-alcoholic fatty liver disease and the associated brain dysfunction. J Hepatol 2023; 78:180-190. [PMID: 35995127 DOI: 10.1016/j.jhep.2022.08.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 07/30/2022] [Accepted: 08/05/2022] [Indexed: 02/01/2023]
Abstract
BACKGROUND & AIMS Non-alcoholic fatty liver disease (NAFLD) has been associated with mild cerebral dysfunction and cognitive decline, although the exact pathophysiological mechanism remains ambiguous. Using a diet-induced model of NAFLD and monocarboxylate transporter-1 (Mct1+/-) haploinsufficient mice, which resist high-fat diet-induced hepatic steatosis, we investigated the hypothesis that NAFLD leads to an encephalopathy by altering cognition, behaviour, and cerebral physiology. We also proposed that global MCT1 downregulation offers cerebral protection. METHODS Behavioural tests were performed in mice following 16 weeks of control diet (normal chow) or high-fat diet with high fructose/glucose in water. Tissue oxygenation, cerebrovascular reactivity, and cerebral blood volume were monitored under anaesthesia by multispectral optoacoustic tomography and optical fluorescence. Cortical mitochondrial oxygen consumption and respiratory capacities were measured using ex vivo high-resolution respirometry. Microglial and astrocytic changes were evaluated by immunofluorescence and 3D reconstructions. Body composition was assessed using EchoMRI, and liver steatosis was confirmed by histology. RESULTS NAFLD concomitant with obesity is associated with anxiety- and depression-related behaviour. Low-grade brain tissue hypoxia was observed, likely attributed to the low-grade brain inflammation and decreased cerebral blood volume. It is also accompanied by microglial and astrocytic morphological and metabolic alterations (higher oxygen consumption), suggesting the early stages of an obesogenic diet-induced encephalopathy. Mct1 haploinsufficient mice, despite fat accumulation in adipose tissue, were protected from NAFLD and associated cerebral alterations. CONCLUSIONS This study provides evidence of compromised brain health in obesity and NAFLD, emphasising the importance of the liver-brain axis. The protective effect of Mct1 haploinsufficiency points to this protein as a novel therapeutic target for preventing and/or treating NAFLD and the associated brain dysfunction. IMPACT AND IMPLICATIONS This study is focused on unravelling the pathophysiological mechanism by which cerebral dysfunction and cognitive decline occurs during NAFLD and exploring the potential of monocarboxylate transporter-1 (MCT1) as a novel preventive or therapeutic target. Our findings point to NAFLD as a serious health risk and its adverse impact on the brain as a potential global health system and economic burden. These results highlight the utility of Mct1 transgenic mice as a model for NAFLD and associated brain dysfunction and call for systematic screening by physicians for early signs of psychological symptoms, and an awareness by individuals at risk of these potential neurological effects. This study is expected to bring attention to the need for early diagnosis and treatment of NAFLD, while having a direct impact on policies worldwide regarding the health risk associated with NAFLD, and its prevention and treatment.
Collapse
Affiliation(s)
- Anna Hadjihambi
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland; The Roger Williams Institute of Hepatology London, Foundation for Liver Research, London, UK; Faculty of Life Sciences and Medicine, King's College London, London, UK.
| | - Christos Konstantinou
- The Roger Williams Institute of Hepatology London, Foundation for Liver Research, London, UK; Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Jan Klohs
- Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland; Neuroscience Centre Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Katia Monsorno
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | | | - Chris Donnelly
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland; Institute of Sports Science, University of Lausanne, Lausanne, Switzerland
| | - I Jane Cox
- The Roger Williams Institute of Hepatology London, Foundation for Liver Research, London, UK; Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Anjali Kusumbe
- Tissue and Tumor Microenvironments Group, MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Patrick S Hosford
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Ugo Soffientini
- The Roger Williams Institute of Hepatology London, Foundation for Liver Research, London, UK; Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Salvatore Lecca
- The Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
| | - Manuel Mameli
- The Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland; Inserm, UMR-S 839, Paris, France
| | - Rajiv Jalan
- Institute for Liver and Digestive Health, Division of Medicine, UCL Medical School, Royal Free Hospital, University College London, London, UK
| | | | - Luc Pellerin
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland; Inserm U1313, Université de Poitiers et CHU de Poitiers, France.
| |
Collapse
|
10
|
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
|
11
|
Monocarboxylate transporters (MCTs) in skeletal muscle and hypothalamus of less or more physically active mice exposed to aerobic training. Life Sci 2022; 307:120872. [PMID: 35948119 DOI: 10.1016/j.lfs.2022.120872] [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: 06/09/2022] [Revised: 07/27/2022] [Accepted: 08/04/2022] [Indexed: 11/22/2022]
Abstract
AIMS The synthesis of monocarboxylate transporters (MCTs) can be stimulated by aerobic training, but few is known about this effect associated or not with non-voluntary daily activities. We examined the effect of eight weeks of aerobic training in MCTs on the skeletal muscle and hypothalamus of less or more physically active mice, which can be achieved by keeping them in two different housing models, a small cage (SC) and a large cage (LC). MAIN METHODS Forty male C57BL/6J mice were divided into four groups. In each housing condition, mice were divided into untrained (N) and trained (T). For 8 weeks, the trained animals ran on a treadmill with an intensity equivalent to 80 % of the individual critical velocity (CV), considered aerobic capacity, 40 min/day, 5 times/week. Protein expression of MCTs was determined with fluorescence Western Blot. KEY FINDINGS T groups had higher hypothalamic MCT2 than N groups (ANOVA, P = 0.032). Significant correlations were detected between hypothalamic MCT2 and CV. There was a difference between the SC and LC groups in relation to MCT4 in the hypothalamus (LC > SC, P = 0.044). Trained mice housed in LC (but not SC-T) exhibited a reduction in MCT4 muscle (P < 0.001). SIGNIFICANCE Our findings indicate that aerobically trained mice increased the expression of MCT2 protein in the hypothalamus, which has been related to the uptake of lactate in neurons. Changes in energy metabolism in physically active mice (kept in LC) may be related to upregulation of hypothalamic MCT4, probably participating in the regulation of satiety.
Collapse
|
12
|
Choi JH, Kim MS. Homeostatic Regulation of Glucose Metabolism by the Central Nervous System. Endocrinol Metab (Seoul) 2022; 37:9-25. [PMID: 35255598 PMCID: PMC8901968 DOI: 10.3803/enm.2021.1364] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 02/07/2022] [Indexed: 12/04/2022] Open
Abstract
Evidence for involvement of the central nervous system (CNS) in the regulation of glucose metabolism dates back to the 19th century, although the majority of the research on glucose metabolism has focused on the peripheral metabolic organs. Due to recent advances in neuroscience, it has now become clear that the CNS is indeed vital for maintaining glucose homeostasis. To achieve normoglycemia, specific populations of neurons and glia in the hypothalamus sense changes in the blood concentrations of glucose and of glucoregulatory hormones such as insulin, leptin, glucagon-like peptide 1, and glucagon. This information is integrated and transmitted to other areas of the brain where it eventually modulates various processes in glucose metabolism (i.e., hepatic glucose production, glucose uptake in the brown adipose tissue and skeletal muscle, pancreatic insulin and glucagon secretion, renal glucose reabsorption, etc.). Errors in these processes lead to hyper- or hypoglycemia. We here review the current understanding of the brain regulation of glucose metabolism.
Collapse
Affiliation(s)
- Jong Han Choi
- Division of Endocrinology and Metabolism, Konkuk University Medical Center, Seoul,
Korea
| | - Min-Seon Kim
- Division of Endocrinology and Metabolism, Asan Medical Center, University of Ulsan College of Medicine, Seoul,
Korea
- Appeptite Regulation Laboratory, Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul,
Korea
| |
Collapse
|
13
|
Does Sertraline Affect Hypothalamic Food Intake Peptides in the Rat Experimental Model of Chronic Mild Stress-Induced Depression? Neurochem Res 2022; 47:1299-1316. [PMID: 35080689 DOI: 10.1007/s11064-022-03529-9] [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: 07/16/2021] [Revised: 01/12/2022] [Accepted: 01/15/2022] [Indexed: 10/19/2022]
Abstract
Depression is a chronic, recurrent and life-threatening disease affecting approximately 15% of the world population. Depression is responsible for neuropathologies like decreased neurogenesis and increased dendritic atrophy. Antidepressant treatments increase hippocampal neurogenesis and neurotrophic factor expression. Based on this information, it was aimed to investigate effect of sertraline on depression in rats with chronic mild stress (CMS) model and to determine how it affects cell proliferation and hypothalamic peptide levels in hypothalamus. 56 adult male Wistar albino; control, depression(D), depression + sertraline, sertraline were divided into groups. Various stressors were applied to D for 30 days. Open field test (OFT) and forced swimming test (FST) were conducted to check whether the animals were depressed. On the 16th day osmotic minipump was placed subcutaneously and sertraline (10 mg/kg/day) was administered for 15 days. Behavior tests were done. Hypothalamic peptide gene expression levels were analyzed by quantitative RT-PCR. Statistical evaluations were made using ANOVA. It caused a decrease in the percentage of movement in the D and control groups in the OFT, an increase in the immobility time in the D group in the FST, and an increase in the swimming behavior in the DS group. Animals did not show any anxiological behavior based on the elevated plus maze test results. CMS caused a decrease in GLUT2 and NPY gene expression in the hypothalamus of animals, an increase in POMC and FGFR2, and an increase in IGFIR and GLUT2 gene expression in the DS group. Sertraline has been shown to ameliorate the effects of CMS-induced depression. Sertraline is thought to have a positive regulatory effect on both the formation of neural precursor cells and the survival of newly formed neurons in the hypothalamus. Newly formed neurons in the hypothalamus express food intake-related NPY, POMC, GLUT2 neurons, and thus hypothalamic tanycytes may play a key role in the control of energy metabolism.
Collapse
|
14
|
Ren Y, Li L, Wan L, Huang Y, Cao S. Glucokinase as an emerging anti-diabetes target and recent progress in the development of its agonists. J Enzyme Inhib Med Chem 2022; 37:606-615. [PMID: 35067153 PMCID: PMC8788356 DOI: 10.1080/14756366.2021.2025362] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Type 2 diabetes mellitus is a metabolic disorder with complicated pathogenesis, and mono-target therapy often fails to effectively manage the levels of blood glucose. In recent years, the anti-diabetes target glucokinase (GK) has attracted the attention of researchers. It acts as a glucose sensor, triggering counter regulatory responses following a change in glucose levels to aid restoration of normoglycemia. Activation of GK induces glucose metabolism and reduces glucose levels for the treatment of type 2 diabetes. GK agonists (GKA) are a new class of antidiabetic drugs. Among these agents, dorzagliatin is currently being investigated in phase III clinical trials, while PB-201 and AZD-1656 have reached phase II clinical trials. This article describes the mechanism of action of GK in diabetes and of action of GKA at the protein level, and provides a review of the research, trends, and prospects regarding the use of GKA in this setting.
Collapse
Affiliation(s)
- Yixin Ren
- Key Laboratory of Green Chemical Engineering Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan, P. R. China
| | - Li Li
- Key Laboratory of Green Chemical Engineering Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan, P. R. China
| | - Li Wan
- Key Laboratory of Green Chemical Engineering Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan, P. R. China
| | - Yan Huang
- Key Laboratory of Green Chemical Engineering Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan, P. R. China
| | - Shuang Cao
- Key Laboratory of Green Chemical Engineering Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan, P. R. China
| |
Collapse
|
15
|
Ullah R, Rauf N, Nabi G, Yi S, Yu-Dong Z, Fu J. Mechanistic insight into high-fat diet-induced metabolic inflammation in the arcuate nucleus of the hypothalamus. Biomed Pharmacother 2021; 142:112012. [PMID: 34388531 DOI: 10.1016/j.biopha.2021.112012] [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: 07/09/2021] [Revised: 07/31/2021] [Accepted: 08/03/2021] [Indexed: 12/16/2022] Open
Abstract
A high-fat diet (HFD) is linked with cytokines production by non-neuronal cells within the hypothalamus, which mediates metabolic inflammation. These cytokines then activate different inflammatory mediators in the arcuate nucleus of the hypothalamus (ARC), a primary hypothalamic area accommodating proopiomelanocortin (POMC) and agouti-related peptide (AGRP) neurons, first-order neurons that sense and integrate peripheral metabolic signals and then respond accordingly. These mediators, such as inhibitor of κB kinase-β (IKKβ), suppression of cytokine signaling 3 (SOCS3), c-Jun N-terminal kinases (JNKs), protein kinase C (PKC), etc., cause insulin and leptin resistance in POMC and AGRP neurons and support obesity and related metabolic complications. On the other hand, inhibition of these mediators has been shown to counteract the impaired metabolism. Therefore, it is important to discuss the contribution of neuronal and non-neuronal cells in HFD-induced hypothalamic inflammation. Furthermore, understanding few other questions, such as the diets causing hypothalamic inflammation, the gender disparity in response to HFD feeding, and how hypothalamic inflammation affects ARC neurons to cause impaired metabolism, will be helpful for the development of therapeutic approaches to prevent or treat HFD-induced obesity.
Collapse
Affiliation(s)
- Rahim Ullah
- Department of Endocrinology, Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310052, China; Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
| | - Naveed Rauf
- Department of Endocrinology, Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310052, China
| | - Ghulam Nabi
- Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Sciences, Hebei Normal University, Shijiazhuang 050024, Hebei Province, China; Department of Life Sciences, School of Science, University of Management and Technology (UMT), Lahore, Pakistan
| | - Shen Yi
- Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China.
| | - Zhou Yu-Dong
- Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China.
| | - Junfen Fu
- Department of Endocrinology, Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310052, China; National Clinical Research Center for Child Health, Hangzhou 310052, China; National Children's Regional Medical Center, Hangzhou 310052, China.
| |
Collapse
|
16
|
Lhomme T, Clasadonte J, Imbernon M, Fernandois D, Sauve F, Caron E, Lima N, Heras V, Martinez-Corral I, Müller-Fielitz H, Rasika S, Schwaninger M, Nogueiras R, Prevot V. Tanycytic networks mediate energy balance by feeding lactate to glucose-insensitive POMC neurons. J Clin Invest 2021; 131:e140521. [PMID: 34324439 DOI: 10.1172/jci140521] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 07/28/2021] [Indexed: 11/17/2022] Open
Abstract
Hypothalamic glucose sensing enables an organism to match energy expenditure and food intake to circulating levels of glucose, the main energy source of the brain. Here, we established that tanycytes of the hypothalamic arcuate nucleus, specialized glia that line the wall of the third ventricle, convert brain glucose supplies into lactate that they transmit through monocarboxylate transporters to arcuate proopiomelanocortin neurons, which integrate this signal to drive their activity and to adapt the metabolic response to meet physiological demands. Furthermore, this transmission required the formation of extensive Connexin-43 gap-junction-mediated metabolic networks by arcuate tanycytes. Selectively suppressing either tanycytic monocarboxylate transporters or gap junctions resulted in altered feeding behavior and energy metabolism. Tanycytic intercellular communication and lactate production are thus integral to the mechanism by which hypothalamic neurons that regulate energy and glucose homeostasis efficiently perceive alterations in systemic glucose levels as a function of the physiological state of the organism.
Collapse
Affiliation(s)
- Tori Lhomme
- Laboratory of Development and Plasticity of the Neuroendocrine Brain, INSERM U1172, Lille, France
| | - Jerome Clasadonte
- Laboratory of Development and Plasticity of the Neuroendocrine Brain, INSERM U1172, Lille, France
| | - Monica Imbernon
- Laboratory of Development and Plasticity of the Neuroendocrine Brain, INSERM U1172, Lille, France
| | - Daniela Fernandois
- Laboratory of Development and Plasticity of the Neuroendocrine Brain, INSERM U1172, Lille, France
| | - Florent Sauve
- Laboratory of Development and Plasticity of the Neuroendocrine Brain, INSERM U1172, Lille, France
| | - Emilie Caron
- Laboratory of Development and Plasticity of the Neuroendocrine Brain, INSERM U1172, Lille, France
| | - Natalia Lima
- CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
| | - Violeta Heras
- CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
| | - Ines Martinez-Corral
- Laboratory of Development and Plasticity of the Neuroendocrine Brain, INSERM U1172, Lille, France
| | - Helge Müller-Fielitz
- Institute for Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Lübeck, Germany
| | - S Rasika
- Laboratory of Development and Plasticity of the Neuroendocrine Brain, INSERM U1172, Lille, France
| | - Markus Schwaninger
- Institute for Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Lübeck, Germany
| | - Ruben Nogueiras
- CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
| | - Vincent Prevot
- Laboratory of Development and Plasticity of the Neuroendocrine Brain, INSERM U1172, Lille, France
| |
Collapse
|
17
|
Salgado M, García-Robles MÁ, Sáez JC. Purinergic signaling in tanycytes and its contribution to nutritional sensing. Purinergic Signal 2021; 17:607-618. [PMID: 34018139 DOI: 10.1007/s11302-021-09791-w] [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: 03/07/2021] [Accepted: 04/19/2021] [Indexed: 10/21/2022] Open
Abstract
Tanycytes are hypothalamic radial glial-like cells with an important role in the regulation of neuroendocrine axes and energy homeostasis. These cells have been implicated in glucose, amino acids, and fatty acid sensing in the hypothalamus of rodents, where they are strategically positioned. While their cell bodies contact the cerebrospinal fluid, their extensive processes contact neurons of the arcuate and ventromedial nuclei, protagonists in the regulation of food intake. A growing body of evidence has shown that purinergic signaling plays a relevant role in this homeostatic role of tanycytes, likely regulating the release of gliotransmitters that will modify the activity of satiety-controlling hypothalamic neurons. Connexin hemichannels have proven to be particularly relevant in these mechanisms since they are responsible for the release of ATP from tanycytes in response to nutritional signals. On the other hand, either ionotropic or metabotropic ATP receptors are involved in the generation of intracellular Ca2+ waves in response to hypothalamic nutrients, which can spread between glial cells and towards neighboring neurons. This review will summarize recent evidence that supports a nutrient sensor role for tanycytes, highlighting the participation of purinergic signaling in this process.
Collapse
Affiliation(s)
- Magdiel Salgado
- Laboratorio de Biología Celular, Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile.,Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - María Á García-Robles
- Laboratorio de Biología Celular, Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile.
| | - Juan C Sáez
- Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile.
| |
Collapse
|
18
|
Hayden MR, Banks WA. Deficient Leptin Cellular Signaling Plays a Key Role in Brain Ultrastructural Remodeling in Obesity and Type 2 Diabetes Mellitus. Int J Mol Sci 2021; 22:5427. [PMID: 34063911 PMCID: PMC8196569 DOI: 10.3390/ijms22115427] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 05/13/2021] [Accepted: 05/15/2021] [Indexed: 12/11/2022] Open
Abstract
The triad of obesity, metabolic syndrome (MetS), Type 2 diabetes mellitus (T2DM) and advancing age are currently global societal problems that are expected to grow over the coming decades. This triad is associated with multiple end-organ complications of diabetic vasculopathy (maco-microvessel disease), neuropathy, retinopathy, nephropathy, cardiomyopathy, cognopathy encephalopathy and/or late-onset Alzheimer's disease. Further, obesity, MetS, T2DM and their complications are associated with economical and individual family burdens. This review with original data focuses on the white adipose tissue-derived adipokine/hormone leptin and how its deficient signaling is associated with brain remodeling in hyperphagic, obese, or hyperglycemic female mice. Specifically, the ultrastructural remodeling of the capillary neurovascular unit, brain endothelial cells (BECs) and their endothelial glycocalyx (ecGCx), the blood-brain barrier (BBB), the ventricular ependymal cells, choroid plexus, blood-cerebrospinal fluid barrier (BCSFB), and tanycytes are examined in female mice with impaired leptin signaling from either dysfunction of the leptin receptor (DIO and db/db models) or the novel leptin deficiency (BTBR ob/ob model).
Collapse
Affiliation(s)
- Melvin R. Hayden
- Departments of Internal Medicine, Endocrinology Diabetes and Metabolism, Diabetes and Cardiovascular Disease Center, University of Missouri-Columbia School of Medicine, One Hospital Drive, Columbia, MO 65212, USA;
| | - William A. Banks
- Geriatrics Research, Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, 1660 S. Columbian Way, 810C/Bldg 1, Seattle, WA 98108, USA
- Department of Medicine, Division of Gerontology and Geriatric Medicine, University of Washington, Seattle, WA 98108, USA
| |
Collapse
|
19
|
Abstract
Chronic metabolic diseases, including diabetes and obesity, have become a major global health threat of the twenty-first century. Maintaining glucose homeostasis is essential for survival in mammals. Complex and highly coordinated interactions between glucose-sensing mechanisms and multiple effector systems are essential for controlling glucose levels in the blood. The central nervous system (CNS) plays a crucial role in regulating glucose homeostasis. Growing evidence indicates that disruption of glucose sensing in selective CNS areas, such as the hypothalamus, is closely interlinked with the pathogenesis of obesity and type 2 diabetes mellitus. However, the underlying intracellular mechanisms of glucose sensing in the hypothalamus remain elusive. Here, we review the current literature on hypothalamic glucose-sensing mechanisms and discuss the impact of alterations of these mechanisms on the pathogenesis of diabetes.
Collapse
Affiliation(s)
- Nal Ae Yoon
- Institute of Human Nutrition, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY, USA
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY, USA
| | - Sabrina Diano
- Institute of Human Nutrition, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY, USA.
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY, USA.
| |
Collapse
|
20
|
Garcia SM, Hirschberg PR, Sarkar P, Siegel DM, Teegala SB, Vail GM, Routh VH. Insulin actions on hypothalamic glucose-sensing neurones. J Neuroendocrinol 2021; 33:e12937. [PMID: 33507001 PMCID: PMC10561189 DOI: 10.1111/jne.12937] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 12/22/2020] [Accepted: 12/29/2020] [Indexed: 12/13/2022]
Abstract
Subsequent to the discovery of insulin 100 years ago, great strides have been made in understanding its function, especially in the brain. It is now clear that insulin is a critical regulator of the neuronal circuitry controlling energy balance and glucose homeostasis. This review focuses on the effects of insulin and diabetes on the activity and glucose sensitivity of hypothalamic glucose-sensing neurones. We highlight the role of electrophysiological data in understanding how insulin regulates glucose-sensing neurones. A brief introduction describing the benefits and limitations of the major electrophysiological techniques used to investigate glucose-sensing neurones is provided. The mechanisms by which hypothalamic neurones sense glucose are discussed with an emphasis on those glucose-sensing neurones already shown to be modulated by insulin. Next, the literature pertaining to how insulin alters the activity and glucose sensitivity of these hypothalamic glucose-sensing neurones is described. In addition, the effects of impaired insulin signalling during diabetes and the ramifications of insulin-induced hypoglycaemia on hypothalamic glucose-sensing neurones are covered. To the extent that it is known, we present hypotheses concerning the mechanisms underlying the effects of these insulin-related pathologies. To conclude, electrophysiological data from the hippocampus are evaluated aiming to provide clues regarding how insulin might influence neuronal plasticity in glucose-sensing neurones. Although much has been accomplished subsequent to the discovery of insulin, the work described in our review suggests that the regulation of central glucose sensing by this hormone is both important and understudied.
Collapse
Affiliation(s)
- Stephanie M Garcia
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Pamela R Hirschberg
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Pallabi Sarkar
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Dashiel M Siegel
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Suraj B Teegala
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Gwyndolin M Vail
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Vanessa H Routh
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| |
Collapse
|
21
|
Sugiura A, Shimizu T, Kameyama T, Maruo T, Kedashiro S, Miyata M, Mizutani K, Takai Y. Identification of Sox2 and NeuN Double-Positive Cells in the Mouse Hypothalamic Arcuate Nucleus and Their Reduction in Number With Aging. Front Aging Neurosci 2021; 12:609911. [PMID: 33776740 PMCID: PMC7991304 DOI: 10.3389/fnagi.2020.609911] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 12/22/2020] [Indexed: 01/17/2023] Open
Abstract
The hypothalamus plays a central role in homeostasis and aging. The hypothalamic arcuate nucleus (ARC) controls homeostasis of food intake and energy expenditure and retains adult neural stem cells (NSCs)/progenitor cells. Aging induces the loss of NSCs and the enhancement of inflammation, including the activation of glial cells in the ARC, but aging-associated alterations of the hypothalamic cells remain obscure. Here, we identified Sox2 and NeuN double-positive cells in a subpopulation of cells in the mouse ARC. These cells were reduced in number with aging, although NeuN-positive neuronal cells were unaltered in the total number. Diet-induced obesity mice fed with high-fat diet presented a similar hypothalamic alteration to aged mice. This study provides a new insight into aging-induced changes in the hypothalamus.
Collapse
Affiliation(s)
- Ayumu Sugiura
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tatsuhiro Shimizu
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Takeshi Kameyama
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tomohiko Maruo
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Shin Kedashiro
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Muneaki Miyata
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kiyohito Mizutani
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yoshimi Takai
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| |
Collapse
|
22
|
Tanycytes in the infundibular nucleus and median eminence and their role in the blood-brain barrier. HANDBOOK OF CLINICAL NEUROLOGY 2021; 180:253-273. [PMID: 34225934 DOI: 10.1016/b978-0-12-820107-7.00016-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The blood-brain barrier is generally attributed to endothelial cells. However, in circumventricular organs, such as the median eminence, tanycytes take over the barrier function. These ependymoglial cells form the wall of the third ventricle and send long extensions into the parenchyma to contact blood vessels and hypothalamic neurons. The shape and location of tanycytes put them in an ideal position to connect the periphery with central nervous compartments. In line with this, tanycytes control the transport of hormones and key metabolites in and out of the hypothalamus. They function as sensors of peripheral homeostasis for central regulatory networks. This chapter discusses current evidence that tanycytes play a key role in regulating glucose balance, food intake, endocrine axes, seasonal changes, reproductive function, and aging. The understanding of how tanycytes perform these diverse tasks is only just beginning to emerge and will probably lead to a more differentiated view of how the brain and the periphery interact.
Collapse
|
23
|
Yoo S, Cha D, Kim S, Jiang L, Cooke P, Adebesin M, Wolfe A, Riddle R, Aja S, Blackshaw S. Tanycyte ablation in the arcuate nucleus and median eminence increases obesity susceptibility by increasing body fat content in male mice. Glia 2020; 68:1987-2000. [PMID: 32173924 PMCID: PMC7423758 DOI: 10.1002/glia.23817] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 02/28/2020] [Accepted: 02/28/2020] [Indexed: 12/11/2022]
Abstract
Tanycytes are radial glial cells located in the mediobasal hypothalamus. Recent studies have proposed that tanycytes play an important role in hypothalamic control of energy homeostasis, although this has not been directly tested. Here, we report the phenotype of mice in which tanycytes of the arcuate nucleus and median eminence were conditionally ablated in adult mice. Although the cerebrospinal fluid-hypothalamic barrier was rendered more permeable following tanycyte ablation, neither the blood-hypothalamic barrier nor leptin-induced pSTAT3 activation in hypothalamic parenchyma were affected. We observed a significant increase in visceral fat distribution accompanying insulin insensitivity in male mice, without significant effect on either body weight or food intake. A high-fat diet tended to accelerate overall body weight gain in tanycyte-ablated mice, but the development of visceral adiposity and insulin insensitivity was comparable to wildtype. Thermoneutral housing exacerbated fat accumulation and produced a shift away from fat oxidation in tanycyte-ablated mice. These results clarify the extent to which tanycytes regulate energy balance, and demonstrate a role for tanycytes in regulating fat metabolism.
Collapse
Affiliation(s)
- Sooyeon Yoo
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - David Cha
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Soohyun Kim
- Department of Orthopedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Lizhi Jiang
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Patrick Cooke
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Mobolanie Adebesin
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Andrew Wolfe
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Ryan Riddle
- Department of Orthopedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Baltimore Veterans Administration Medical Center, Baltimore, Maryland
| | - Susan Aja
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Seth Blackshaw
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Center for Human Systems Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland
| |
Collapse
|
24
|
Bentsen MA, Rausch DM, Mirzadeh Z, Muta K, Scarlett JM, Brown JM, Herranz-Pérez V, Baquero AF, Thompson J, Alonge KM, Faber CL, Kaiyala KJ, Bennett C, Pyke C, Ratner C, Egerod KL, Holst B, Meek TH, Kutlu B, Zhang Y, Sparso T, Grove KL, Morton GJ, Kornum BR, García-Verdugo JM, Secher A, Jorgensen R, Schwartz MW, Pers TH. Transcriptomic analysis links diverse hypothalamic cell types to fibroblast growth factor 1-induced sustained diabetes remission. Nat Commun 2020; 11:4458. [PMID: 32895383 PMCID: PMC7477234 DOI: 10.1038/s41467-020-17720-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 07/15/2020] [Indexed: 12/26/2022] Open
Abstract
In rodent models of type 2 diabetes (T2D), sustained remission of hyperglycemia can be induced by a single intracerebroventricular (icv) injection of fibroblast growth factor 1 (FGF1), and the mediobasal hypothalamus (MBH) was recently implicated as the brain area responsible for this effect. To better understand the cellular response to FGF1 in the MBH, we sequenced >79,000 single-cell transcriptomes from the hypothalamus of diabetic Lepob/ob mice obtained on Days 1 and 5 after icv injection of either FGF1 or vehicle. A wide range of transcriptional responses to FGF1 was observed across diverse hypothalamic cell types, with glial cell types responding much more robustly than neurons at both time points. Tanycytes and ependymal cells were the most FGF1-responsive cell type at Day 1, but astrocytes and oligodendrocyte lineage cells subsequently became more responsive. Based on histochemical and ultrastructural evidence of enhanced cell-cell interactions between astrocytes and Agrp neurons (key components of the melanocortin system), we performed a series of studies showing that intact melanocortin signaling is required for the sustained antidiabetic action of FGF1. These data collectively suggest that hypothalamic glial cells are leading targets for the effects of FGF1 and that sustained diabetes remission is dependent on intact melanocortin signaling.
Collapse
MESH Headings
- Agouti-Related Protein/metabolism
- Animals
- Astrocytes/drug effects
- Astrocytes/metabolism
- Blood Glucose/analysis
- Cell Communication
- Cell Nucleus/drug effects
- Cell Nucleus/metabolism
- Diabetes Mellitus, Experimental/blood
- Diabetes Mellitus, Experimental/diet therapy
- Diabetes Mellitus, Experimental/etiology
- Diabetes Mellitus, Experimental/pathology
- Diabetes Mellitus, Type 2/blood
- Diabetes Mellitus, Type 2/drug therapy
- Diabetes Mellitus, Type 2/etiology
- Diabetes Mellitus, Type 2/pathology
- Diet, High-Fat/adverse effects
- Dietary Sucrose/administration & dosage
- Dietary Sucrose/adverse effects
- Fibroblast Growth Factor 1/administration & dosage
- Humans
- Hypoglycemic Agents/administration & dosage
- Hypothalamus/cytology
- Hypothalamus/drug effects
- Hypothalamus/pathology
- Injections, Intraventricular
- Leptin/genetics
- Male
- Melanocortins/metabolism
- Melanocyte-Stimulating Hormones/administration & dosage
- Mice
- Mice, Knockout
- Neurons/drug effects
- Neurons/metabolism
- Oligodendroglia/drug effects
- Oligodendroglia/metabolism
- RNA-Seq
- Receptor, Melanocortin, Type 4/genetics
- Receptors, Melanocortin/antagonists & inhibitors
- Receptors, Melanocortin/metabolism
- Recombinant Proteins/administration & dosage
- Remission Induction/methods
- Signal Transduction/drug effects
- Single-Cell Analysis
- Stereotaxic Techniques
- Transcriptome/drug effects
Collapse
Affiliation(s)
- Marie A Bentsen
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA, USA
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Dylan M Rausch
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Kenjiro Muta
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA, USA
- Chakri Naruebodindra Medical Institute, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Jarrad M Scarlett
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA, USA
- Department of Pediatric Gastroenterology and Hepatology, Seattle Children's Hospital, Seattle, WA, USA
| | - Jenny M Brown
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA, USA
| | - Vicente Herranz-Pérez
- Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, Valencia, Spain
- Predepartamental Unit of Medicine, Jaume I University, Castelló de la Plana, Spain
| | - Arian F Baquero
- Obesity Research Unit, Novo Nordisk Research Center Seattle, Inc., Seattle, WA, USA
| | - Jonatan Thompson
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kimberly M Alonge
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA, USA
| | - Chelsea L Faber
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA, USA
| | - Karl J Kaiyala
- Department of Oral Health Sciences, School of Dentistry, University of Washington, Seattle, WA, USA
| | - Camdin Bennett
- Obesity Research Unit, Novo Nordisk Research Center Seattle, Inc., Seattle, WA, USA
| | - Charles Pyke
- Pathology & Imaging, Global Discovery and Development Sciences, Novo Nordisk A/S, Maaloev, Denmark
| | - Cecilia Ratner
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kristoffer L Egerod
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Birgitte Holst
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas H Meek
- Obesity Research Unit, Novo Nordisk Research Center Seattle, Inc., Seattle, WA, USA
| | - Burak Kutlu
- Obesity Research Unit, Novo Nordisk Research Center Seattle, Inc., Seattle, WA, USA
| | - Yu Zhang
- Obesity Research Unit, Novo Nordisk Research Center Seattle, Inc., Seattle, WA, USA
| | - Thomas Sparso
- Bioinformatics and Data Mining, Global Research Technologies, Novo Nordisk A/S, Maaloev, Denmark
| | - Kevin L Grove
- Obesity Research Unit, Novo Nordisk Research Center Seattle, Inc., Seattle, WA, USA
| | - Gregory J Morton
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA, USA
| | - Birgitte R Kornum
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | | | - Anna Secher
- Diabetes Research, Global Drug Discovery, Novo Nordisk A/S, Maaloev, Denmark
| | - Rasmus Jorgensen
- Diabetes Research, Global Drug Discovery, Novo Nordisk A/S, Maaloev, Denmark
- Cytoki Pharma, Copenhagen, Denmark
| | - Michael W Schwartz
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA, USA.
| | - Tune H Pers
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| |
Collapse
|
25
|
Poddar J, Singh S, Kumar P, Bali S, Gupta S, Chakrabarti S. Inhibition of complex I-III activity of brain mitochondria after intracerebroventricular administration of streptozotocin in rats is possibly related to loss of body weight. Heliyon 2020; 6:e04490. [PMID: 32743098 PMCID: PMC7387826 DOI: 10.1016/j.heliyon.2020.e04490] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 04/30/2020] [Accepted: 07/14/2020] [Indexed: 02/06/2023] Open
Abstract
The effects of streptozotocin (STZ) on the brain after intracerebroventricular (ICV) administration in rodents have been suggested to mimic the pathogenesis of sporadic Alzheimer's disease (AD). Oxidative damage, decreased glucose utilization, mitochondrial bioenergetic changes, neuroinflammation and behavioral impairment have been reported in rodents after ICV-STZ administration. However, the molecular mechanisms of STZ effects on brain after ICV administration remain highly controversial. In this study we re-examined several bioenergetic parameters of rat brain mitochondria on day 15 following ICV-STZ treatment. We observed only a moderate but statistically significant decrease in complex I-III activity in brain mitochondria from streptozotocin-treated rats. There were no changes in complex II-III activity or phosphorylation capacity of brain mitochondria after streptozotocin treatment. More importantly, it was observed that ICV-STZ treatment caused variable degrees of body-weight loss in rats, and complex I-III activity was decreased only in those rats showing a significant (more than 10%-35%) loss in body-weights.
Collapse
Affiliation(s)
- Jit Poddar
- Department of Biochemistry, Institute of Post-graduate Medical Education & Research, Kolkata, India.,Department of Biochemistry, M M Institute of Medical Sciences & Research, Maharishi Markandeshwar Deemed University, Mullana, Ambala, India
| | - Sukhpal Singh
- Department of Biochemistry, M M Institute of Medical Sciences & Research, Maharishi Markandeshwar Deemed University, Mullana, Ambala, India
| | - Pardeep Kumar
- Department of Biochemistry, M M Institute of Medical Sciences & Research, Maharishi Markandeshwar Deemed University, Mullana, Ambala, India
| | - Sharadendu Bali
- Department of Surgery, M M Institute of Medical Sciences & Research, Maharishi Markandeshwar Deemed University, Mullana, Ambala, India
| | - Sumeet Gupta
- M M College of Pharmacy, Maharishi Markandeshwar Deemed University, Mullana, Ambala, India
| | - Sasanka Chakrabarti
- Department of Biochemistry, M M Institute of Medical Sciences & Research, Maharishi Markandeshwar Deemed University, Mullana, Ambala, India
| |
Collapse
|
26
|
Yuan X, Bhat OM, Lohner H, Zhang Y, Li PL. Downregulation of Lysosomal Acid Ceramidase Mediates HMGB1-Induced Migration and Proliferation of Mouse Coronary Arterial Myocytes. Front Cell Dev Biol 2020; 8:111. [PMID: 32211403 PMCID: PMC7076051 DOI: 10.3389/fcell.2020.00111] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 02/10/2020] [Indexed: 01/07/2023] Open
Abstract
High-mobility group box 1 protein (HMGB1) has been reported to trigger lysosome destabilization causing a wide of inflammatory diseases. The present study tested whether a lysosomal enzyme, acid ceramidase (AC), plays a critical role in HMGB1-induced alteration in ceramide metabolism and whether such HMGB1-AC interaction is associated with abnormal migration and proliferation of vascular smooth muscle cells (SMCs). We first observed that the expression of AC in the medial layer of mouse coronary arterial wall and colocalization of AC with a lysosome marker Lamp-1. In primary cultured coronary arterial myocytes (CAMs), AC expression and colocalization with Lamp-1 were significantly up-regulated by AC inducer, genistein, but down-regulated by AC inhibitor, N-oleoylethanolamine (NOE). HMGB1 dose-dependently decreased the colocalization of AC with Lamp-1 and reduced mRNA and protein expressions of AC in CAMs, but reversed by genistein. Consistently, HMGB1 significantly induced increases in the levels of long-chain ceramides in CAMs, which were not further enhanced by NOE but blocked by genistein. More importantly, HMGB1 promoted migration and proliferation of CAMs, which were not further increased by NOE but reduced by genistein. Lastly, CAMs isolated from smooth muscle-specific AC knockout mice (AC gene Asah1) exhibited increased ceramide levels and enhanced the migration and proliferation, which resembles the effects of HMGB1 on wild-type CAMs. Together, these results suggest that HMGB1 promotes SMC migration and proliferation via inhibition of AC expression and ceramide accumulation.
Collapse
Affiliation(s)
- Xinxu Yuan
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States
| | - Owais M Bhat
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States
| | - Hannah Lohner
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States
| | - Yang Zhang
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, TX, United States
| | - Pin-Lan Li
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States
| |
Collapse
|
27
|
Chowen JA, Garcia-Segura LM. Microglia, neurodegeneration and loss of neuroendocrine control. Prog Neurobiol 2020; 184:101720. [DOI: 10.1016/j.pneurobio.2019.101720] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 10/19/2019] [Accepted: 11/02/2019] [Indexed: 02/07/2023]
|
28
|
Richter J, Rabe D, Duysen K, Melchert UH, Oltmanns KM. Lactate infusion increases brain energy content during euglycemia but not hypoglycemia in healthy men. NMR IN BIOMEDICINE 2019; 32:e4167. [PMID: 31468650 DOI: 10.1002/nbm.4167] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 07/04/2019] [Accepted: 07/24/2019] [Indexed: 06/10/2023]
Abstract
A special characteristic of the brain is the usage of lactate as alternative fuel instead of glucose to preserve its energy homeostasis. This physiological function is valid for sufficient cerebral glucose supply, as well as presumably during hypoglycemia, given that exogenous lactate infusion suppresses hormonal counterregulation. However, it is not yet clarified whether this effect is mediated by the use of lactate as an alternative cerebral energy substrate or any other mechanism. We hypothesized that under conditions of limited access to glucose (ie, during experimental hypoglycemia) lactate infusion would prevent hypoglycemia-induced neuroenergetic deficits in a neuroprotective way. In a randomized, double-blind, crossover study, lactate vs placebo infusion was compared during hyperinsulinemic-hypoglycemic clamps in 16 healthy young men. We measured the cerebral high-energy phosphate content - ie, adenosine triphosphate (ATP), phosphocreatine (PCr) and inorganic phosphate (Pi) levels - by 31 P-magnetic resonance spectroscopy as well as the neuroendocrine stress response. During euglycemia, lactate infusion increased ATP/Pi as well as PCr/Pi ratios compared with baseline values and placebo infusion. During hypoglycemia, there were no differences between the lactate and the placebo condition in both ratios. Hormonal counterregulation was significantly diminished upon lactate infusion. Our data demonstrate an elevated cerebral high-energy phosphate content upon lactate infusion during euglycemia, whereas there was no such effect during experimental hypoglycemia. Nevertheless, lactate infusion suppressed hypoglycemic hormonal counterregulation. Lactate thus adds to cerebral energy provision during euglycemia and may contribute to an increase in ATP reserves, which in turn protects the brain against neuroglucopenia under recurrent hypopglycemic conditions, eg, in diabetic patients.
Collapse
Affiliation(s)
- Juliane Richter
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
| | - Doerte Rabe
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
| | - Kai Duysen
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
| | - Uwe H Melchert
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
| | - Kerstin M Oltmanns
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
| |
Collapse
|
29
|
Kim S, Kim N, Park S, Jeon Y, Lee J, Yoo SJ, Lee JW, Moon C, Yu SW, Kim EK. Tanycytic TSPO inhibition induces lipophagy to regulate lipid metabolism and improve energy balance. Autophagy 2019; 16:1200-1220. [PMID: 31469345 PMCID: PMC7469491 DOI: 10.1080/15548627.2019.1659616] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Hypothalamic glial cells named tanycytes, which line the 3rd ventricle (3V), are components of the hypothalamic network that regulates a diverse array of metabolic functions for energy homeostasis. Herein, we report that TSPO (translocator protein), an outer mitochondrial protein, is highly enriched in tanycytes and regulates homeostatic responses to nutrient excess as a potential target for an effective intervention in obesity. Administration of a TSPO ligand, PK11195, into the 3V, and tanycyte-specific deletion of Tspo reduced food intake and elevated energy expenditure, leading to negative energy balance in a high-fat diet challenge. Ablation of tanycytic Tspo elicited AMPK-dependent lipophagy, breaking down lipid droplets into free fatty acids, thereby elevating ATP in a lipid stimulus. Our findings suggest that tanycytic TSPO affects systemic energy balance through macroautophagy/autophagy-regulated lipid metabolism, and highlight the physiological significance of TSPO in hypothalamic lipid sensing and bioenergetics in response to overnutrition. Abbreviations 3V: 3rd ventricle; ACAC: acetyl-Coenzyme A carboxylase; AGRP: agouti related neuropeptide; AIF1/IBA1: allograft inflammatory factor 1; AMPK: AMP-activated protein kinase; ARC: arcuate nucleus; Atg: autophagy related; Bafilo: bafilomycin A1; CAMKK2: calcium/calmodulin-dependent protein kinase kinase 2, beta; CCCP: carbonyl cyanide m-chlorophenylhydrazone; CNS: central nervous system; COX4I1: cytochrome c oxidase subunit 4I1; FFA: free fatty acid; GFAP: glial fibrillary acidic protein; HFD: high-fat diet; ICV: intracerebroventricular; LAMP2: lysosomal-associated membrane protein 2; LD: lipid droplet; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; MBH: mediobasal hypothalamus; ME: median eminence; MEF: mouse embryonic fibroblast; NCD: normal chow diet; NEFM/NFM: neurofilament medium; NPY: neuropeptide Y; OL: oleic acid; POMC: pro-opiomelanocortin-alpha; PRKN/Parkin: parkin RBR E3 ubiquitin protein ligase; Rax: retina and anterior neural fold homeobox; RBFOX3/NeuN: RNA binding protein, fox-1 homolog (C. elegans) 3; RER: respiratory exchange ratio; siRNA: small interfering RNA; SQSTM1: sequestosome 1; TG: triglyceride; TSPO: translocator protein; ULK1: unc-51 like kinase 1; VCO2: carbon dioxide production; VMH: ventromedial hypothalamus; VO2: oxygen consumption
Collapse
Affiliation(s)
- Seolsong Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology , Daegu, Republic of Korea
| | - Nayoun Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology , Daegu, Republic of Korea
| | - Seokjae Park
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology , Daegu, Republic of Korea.,Neurometabolomics Research Center, Daegu Gyeongbuk Institute of Science and Technology , Daegu, Republic of Korea
| | - Yoonjeong Jeon
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology , Daegu, Republic of Korea.,Neurometabolomics Research Center, Daegu Gyeongbuk Institute of Science and Technology , Daegu, Republic of Korea
| | - Jaemeun Lee
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology , Daegu, Republic of Korea
| | - Seung-Jun Yoo
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology , Daegu, Republic of Korea.,Convergence Research Advanced Centre for Olfaction, Daegu Gyeongbuk Institute of Science and Technology , Daegu, Republic of Korea
| | - Ji-Won Lee
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology , Daegu, Republic of Korea
| | - Cheil Moon
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology , Daegu, Republic of Korea.,Convergence Research Advanced Centre for Olfaction, Daegu Gyeongbuk Institute of Science and Technology , Daegu, Republic of Korea
| | - Seong-Woon Yu
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology , Daegu, Republic of Korea.,Neurometabolomics Research Center, Daegu Gyeongbuk Institute of Science and Technology , Daegu, Republic of Korea
| | - Eun-Kyoung Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology , Daegu, Republic of Korea.,Neurometabolomics Research Center, Daegu Gyeongbuk Institute of Science and Technology , Daegu, Republic of Korea
| |
Collapse
|
30
|
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
|
31
|
Fuente-Martín E, Mellado-Gil JM, Cobo-Vuilleumier N, Martín-Montalvo A, Romero-Zerbo SY, Diaz Contreras I, Hmadcha A, Soria B, Martin Bermudo F, Reyes JC, Bermúdez-Silva FJ, Lorenzo PI, Gauthier BR. Dissecting the Brain/Islet Axis in Metabesity. Genes (Basel) 2019; 10:genes10050350. [PMID: 31072002 PMCID: PMC6562925 DOI: 10.3390/genes10050350] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 05/02/2019] [Accepted: 05/02/2019] [Indexed: 12/17/2022] Open
Abstract
The high prevalence of type 2 diabetes mellitus (T2DM), together with the fact that current treatments are only palliative and do not avoid major secondary complications, reveals the need for novel approaches to treat the cause of this disease. Efforts are currently underway to identify therapeutic targets implicated in either the regeneration or re-differentiation of a functional pancreatic islet β-cell mass to restore insulin levels and normoglycemia. However, T2DM is not only caused by failures in β-cells but also by dysfunctions in the central nervous system (CNS), especially in the hypothalamus and brainstem. Herein, we review the physiological contribution of hypothalamic neuronal and glial populations, particularly astrocytes, in the control of the systemic response that regulates blood glucose levels. The glucosensing capacity of hypothalamic astrocytes, together with their regulation by metabolic hormones, highlights the relevance of these cells in the control of glucose homeostasis. Moreover, the critical role of astrocytes in the response to inflammation, a process associated with obesity and T2DM, further emphasizes the importance of these cells as novel targets to stimulate the CNS in response to metabesity (over-nutrition-derived metabolic dysfunctions). We suggest that novel T2DM therapies should aim at stimulating the CNS astrocytic response, as well as recovering the functional pancreatic β-cell mass. Whether or not a common factor expressed in both cell types can be feasibly targeted is also discussed.
Collapse
Affiliation(s)
- Esther Fuente-Martín
- Andalusian Center of Molecular Biology and Regenerative Medicine-CABIMER, Junta de Andalucia-University of Pablo de Olavide-University of Seville-CSIC, 41092 Seville, Spain.
| | - Jose M Mellado-Gil
- Andalusian Center of Molecular Biology and Regenerative Medicine-CABIMER, Junta de Andalucia-University of Pablo de Olavide-University of Seville-CSIC, 41092 Seville, Spain.
| | - Nadia Cobo-Vuilleumier
- Andalusian Center of Molecular Biology and Regenerative Medicine-CABIMER, Junta de Andalucia-University of Pablo de Olavide-University of Seville-CSIC, 41092 Seville, Spain.
| | - Alejandro Martín-Montalvo
- Andalusian Center of Molecular Biology and Regenerative Medicine-CABIMER, Junta de Andalucia-University of Pablo de Olavide-University of Seville-CSIC, 41092 Seville, Spain.
| | - Silvana Y Romero-Zerbo
- Instituto de Investigación Biomédica de Málaga-IBIMA, UGC Endocrinología y Nutrición. Hospital Regional Universitario de Málaga, 29009 Málaga, Spain.
| | - Irene Diaz Contreras
- Andalusian Center of Molecular Biology and Regenerative Medicine-CABIMER, Junta de Andalucia-University of Pablo de Olavide-University of Seville-CSIC, 41092 Seville, Spain.
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28029 Madrid, Spain.
| | - Abdelkrim Hmadcha
- Andalusian Center of Molecular Biology and Regenerative Medicine-CABIMER, Junta de Andalucia-University of Pablo de Olavide-University of Seville-CSIC, 41092 Seville, Spain.
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28029 Madrid, Spain.
| | - Bernat Soria
- Andalusian Center of Molecular Biology and Regenerative Medicine-CABIMER, Junta de Andalucia-University of Pablo de Olavide-University of Seville-CSIC, 41092 Seville, Spain.
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28029 Madrid, Spain.
| | - Francisco Martin Bermudo
- Andalusian Center of Molecular Biology and Regenerative Medicine-CABIMER, Junta de Andalucia-University of Pablo de Olavide-University of Seville-CSIC, 41092 Seville, Spain.
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28029 Madrid, Spain.
| | - Jose C Reyes
- Andalusian Center of Molecular Biology and Regenerative Medicine-CABIMER, Junta de Andalucia-University of Pablo de Olavide-University of Seville-CSIC, 41092 Seville, Spain.
| | - Francisco J Bermúdez-Silva
- Instituto de Investigación Biomédica de Málaga-IBIMA, UGC Endocrinología y Nutrición. Hospital Regional Universitario de Málaga, 29009 Málaga, Spain.
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28029 Madrid, Spain.
| | - Petra I Lorenzo
- Andalusian Center of Molecular Biology and Regenerative Medicine-CABIMER, Junta de Andalucia-University of Pablo de Olavide-University of Seville-CSIC, 41092 Seville, Spain.
| | - Benoit R Gauthier
- Andalusian Center of Molecular Biology and Regenerative Medicine-CABIMER, Junta de Andalucia-University of Pablo de Olavide-University of Seville-CSIC, 41092 Seville, Spain.
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28029 Madrid, Spain.
| |
Collapse
|
32
|
Brown JM, Scarlett JM, Matsen ME, Nguyen HT, Secher A, Jorgensen R, Morton GJ, Schwartz MW. The Hypothalamic Arcuate Nucleus-Median Eminence Is a Target for Sustained Diabetes Remission Induced by Fibroblast Growth Factor 1. Diabetes 2019; 68:1054-1061. [PMID: 30796029 PMCID: PMC6477902 DOI: 10.2337/db19-0025] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 02/14/2019] [Indexed: 12/13/2022]
Abstract
In rodent models of type 2 diabetes (T2D), sustained remission of diabetic hyperglycemia can be induced by a single intracerebroventricular (icv) injection of fibroblast growth factor 1 (FGF1). To identify the brain areas responsible for this effect, we first used immunohistochemistry to map the hypothalamic distribution of phosphorylated extracellular signal-related kinase 1/2 (pERK1/2), a marker of mitogen-activated protein kinase-ERK signal transduction downstream of FGF receptor activation. Twenty minutes after icv FGF1 injection in adult male Wistar rats, pERK1/2 staining was detected primarily in two hypothalamic areas: the arcuate nucleus-median eminence (ARC-ME) and the paraventricular nucleus (PVN). To determine whether an action of FGF1 localized to either the ARC-ME or the PVN is capable of mimicking the sustained antidiabetic effect elicited by icv FGF1, we microinjected either saline vehicle or a low dose of FGF1 (0.3 µg/side) bilaterally into either the ARC-ME area or PVN of Zucker Diabetic Fatty rats, a model of T2D, and monitored daily food intake, body weight, and blood glucose levels over a 3-week period. Whereas bilateral intra-arcuate microinjection of saline vehicle was without effect, remission of hyperglycemia lasting >3 weeks was observed following bilateral microinjection of FGF1 into the ARC-ME. This antidiabetic effect cannot be attributed to leakage of FGF1 into cerebrospinal fluid and subsequent action on other brain areas, since icv injection of the same total dose was without effect. Combined with our finding that bilateral microinjection of the same dose of FGF1 into the PVN was without effect on glycemia or other parameters, we conclude that the ARC-ME area (but not the PVN) is a target for sustained remission of diabetic hyperglycemia induced by FGF1.
Collapse
Affiliation(s)
- Jenny M Brown
- Department of Medicine, UW Medicine Diabetes Institute, University of Washington, Seattle, WA
| | - Jarrad M Scarlett
- Department of Medicine, UW Medicine Diabetes Institute, University of Washington, Seattle, WA
- Department of Pediatric Gastroenterology and Hepatology, University of Washington, Seattle, WA
| | - Miles E Matsen
- Department of Medicine, UW Medicine Diabetes Institute, University of Washington, Seattle, WA
| | - Hong T Nguyen
- Department of Medicine, UW Medicine Diabetes Institute, University of Washington, Seattle, WA
| | - Anna Secher
- Diabetes Research, Global Drug Discovery, Novo Nordisk, Måløv, Denmark
| | - Rasmus Jorgensen
- Diabetes Research, Global Drug Discovery, Novo Nordisk, Måløv, Denmark
| | - Gregory J Morton
- Department of Medicine, UW Medicine Diabetes Institute, University of Washington, Seattle, WA
| | - Michael W Schwartz
- Department of Medicine, UW Medicine Diabetes Institute, University of Washington, Seattle, WA
| |
Collapse
|
33
|
Hultman K, Scarlett JM, Baquero AF, Cornea A, Zhang Y, Salinas CBG, Brown J, Morton GJ, Whalen EJ, Grove KL, Koegler FH, Schwartz MW, Mercer AJ. The central fibroblast growth factor receptor/beta klotho system: Comprehensive mapping in Mus musculus and comparisons to nonhuman primate and human samples using an automated in situ hybridization platform. J Comp Neurol 2019; 527:2069-2085. [PMID: 30809795 DOI: 10.1002/cne.24668] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 02/20/2019] [Accepted: 02/20/2019] [Indexed: 12/25/2022]
Abstract
Central activation of fibroblast growth factor (FGF) receptors regulates peripheral glucose homeostasis and reduces food intake in preclinical models of obesity and diabetes. The current work was undertaken to advance our understanding of the receptor expression, as sites of ligand action by FGF19, FGF21, and FGF1 in the mammalian brain remains unresolved. Recent advances in automated RNAscope in situ hybridization and droplet digital PCR (ddPCR) technology allowed us to interrogate central FGFR/beta klotho (Klb) system at the cellular level in the mouse, with relevant comparisons to nonhuman primate and human brain. FGFR1-3 gene expression was broadly distributed throughout the CNS in Mus musculus, with FGFR1 exhibiting the greatest heterogeneity. FGFR4 expression localized only in the medial habenula and subcommissural organ of mice. Likewise, Klb mRNA was restricted to the suprachiasmatic nucleus (SCh) and select midbrain and hindbrain nuclei. ddPCR in the rodent hypothalamus confirmed that, although expression levels are indeed low for Klb, there is nonetheless a bonafide subpopulation of Klb+ cells in the hypothalamus. In NHP and human midbrain and hindbrain, Klb + cells are quite rare, as is expression of FGFR4. Collectively, these data provide the most robust central map of the FGFR/Klb system to date and highlight central regions that may be of critical importance to assess central ligand effects with pharmacological dosing, such as the putative interactions between the endocrine FGFs and FGFR1/Klb, or FGF19 with FGFR4.
Collapse
Affiliation(s)
| | - Jarrad M Scarlett
- Diabetes & Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington.,Department of Pediatric Gastroenterology & Hepatology, Seattle Children's Hospital, Seattle, Washington
| | - Arian F Baquero
- Novo Nordisk Research Center Seattle, Inc., Seattle, Washington
| | - Anda Cornea
- Novo Nordisk Research Center Seattle, Inc., Seattle, Washington
| | - Yu Zhang
- Novo Nordisk Research Center Seattle, Inc., Seattle, Washington
| | | | - Jenny Brown
- Diabetes & Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington
| | - Gregory J Morton
- Diabetes & Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington
| | - Erin J Whalen
- Novo Nordisk Research Center Seattle, Inc., Seattle, Washington
| | - Kevin L Grove
- Novo Nordisk Research Center Seattle, Inc., Seattle, Washington
| | - Frank H Koegler
- Novo Nordisk Research Center Seattle, Inc., Seattle, Washington
| | - Michael W Schwartz
- Diabetes & Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington
| | - Aaron J Mercer
- Novo Nordisk Research Center Seattle, Inc., Seattle, Washington
| |
Collapse
|
34
|
Langlet F. Tanycyte Gene Expression Dynamics in the Regulation of Energy Homeostasis. Front Endocrinol (Lausanne) 2019; 10:286. [PMID: 31133987 PMCID: PMC6514105 DOI: 10.3389/fendo.2019.00286] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 04/18/2019] [Indexed: 01/01/2023] Open
Abstract
Animal survival relies on a constant balance between energy supply and energy expenditure, which is controlled by several neuroendocrine functions that integrate metabolic information and adapt the response of the organism to physiological demands. Polarized ependymoglial cells lining the floor of the third ventricle and sending a single process within metabolic hypothalamic parenchyma, tanycytes are henceforth described as key components of the hypothalamic neural network controlling energy balance. Their strategic position and peculiar properties convey them diverse physiological functions ranging from blood/brain traffic controllers, metabolic modulators, and neural stem/progenitor cells. At the molecular level, these functions rely on an accurate regulation of gene expression. Indeed, tanycytes are characterized by their own molecular signature which is mostly associated to their diverse physiological functions, and the detection of variations in nutrient/hormone levels leads to an adequate modulation of genetic profile in order to ensure energy homeostasis. The aim of this review is to summarize recent knowledge on the nutritional control of tanycyte gene expression.
Collapse
|
35
|
Otero-Rodiño C, Rocha A, Sánchez E, Álvarez-Otero R, Soengas JL, Cerdá-Reverter JM. Sensing Glucose in the Central Melanocortin Circuits of Rainbow Trout: A Morphological Study. Front Endocrinol (Lausanne) 2019; 10:254. [PMID: 31057490 PMCID: PMC6482260 DOI: 10.3389/fendo.2019.00254] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 04/02/2019] [Indexed: 12/29/2022] Open
Abstract
In mammals, glucosensing markers reside in brain areas known to play an important role in the control of food intake. The best characterized glucosensing mechanism is that dependent on glucokinase (GK) whose activation by increased levels of glucose leads in specific hypothalamic neurons to decreased or increased activity, ultimately leading to decreased food intake. In fish, evidence obtained in recent years suggested the presence of GK-like immunoreactive cells in different brain areas related to food intake control. However, it has not been established yet whether or not those neuronal populations having glucosensing capacity are the same that express the neuropeptides involved in the metabolic control of food intake. Therefore, we assessed through dual fluorescent in situ hybridization the possible expression of GK in the melanocortinergic neurons expressing proopiomelanocortin (POMC) or agouti-related protein (AGRP). POMC and AGRP expression localized exclusively in the rostral hypothalamus, in the ventral pole of the lateral tuberal nucleus, the homolog of the mammalian arcuate nucleus. Hypothalamic GK expression confined to the ependymal cells coating the ventral pole of the third ventricle but some expression level occurred in the AGRP neurons. GK expression seems to be absent in the hypothalamic POMC neurons. These results suggest that AGRP neurons might sense glucose directly through a mechanism involving GK. In contrast, POMC neurons would not directly respond to glucose through GK and would require presynaptic inputs to sense glucose. Ependymal cells could play a critical role relying glucose metabolic information to the central circuitry regulating food intake in fish, especially in POMC neurons.
Collapse
Affiliation(s)
- Cristina Otero-Rodiño
- Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía and Centro de Investigación Mariña, Universidade de Vigo, Vigo, Spain
- *Correspondence: Cristina Otero-Rodiño
| | - Ana Rocha
- Grupo Control de Ingesta, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Departamento de Fisiología y Biotecnología de Peces, Instituto de Acuicultura de Torre de la Sal, Castellón, Spain
| | - Elisa Sánchez
- Grupo Control de Ingesta, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Departamento de Fisiología y Biotecnología de Peces, Instituto de Acuicultura de Torre de la Sal, Castellón, Spain
| | - Rosa Álvarez-Otero
- Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía and Centro de Investigación Mariña, Universidade de Vigo, Vigo, Spain
| | - José L. Soengas
- Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía and Centro de Investigación Mariña, Universidade de Vigo, Vigo, Spain
| | - José M. Cerdá-Reverter
- Grupo Control de Ingesta, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Departamento de Fisiología y Biotecnología de Peces, Instituto de Acuicultura de Torre de la Sal, Castellón, Spain
- José M. Cerdá-Reverter
| |
Collapse
|
36
|
Elizondo-Vega RJ, Recabal A, Oyarce K. Nutrient Sensing by Hypothalamic Tanycytes. Front Endocrinol (Lausanne) 2019; 10:244. [PMID: 31040827 PMCID: PMC6476911 DOI: 10.3389/fendo.2019.00244] [Citation(s) in RCA: 25] [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: 01/17/2019] [Accepted: 03/27/2019] [Indexed: 01/28/2023] Open
Abstract
Nutritional signals have long been implicated in the control of cellular processes that take place in the hypothalamus. This includes food intake regulation and energy balance, inflammation, and most recently, neurogenesis. One of the main glial cells residing in the hypothalamus are tanycytes, radial glial-like cells, whose bodies are located in the lining of the third ventricle, with processes extending to the parenchyma and reaching neuronal nuclei. Their unique anatomical location makes them directly exposed to nutrients in the cerebrospinal fluid. Several research groups have shown that tanycytes can respond to nutritional signals by different mechanisms, such as calcium signaling, metabolic shift, and changes in proliferation/differentiation potential. Despite cumulative evidence showing tanycytes have the molecular components to participate in nutrient detection and response, there are no enough functional studies connecting tanycyte nutrient sensing with hypothalamic functions, nor that highlight the relevance of this process in physiological and pathological context. This review will summarize recent evidence that supports a nutrient sensor role for tanycytes in the hypothalamus, highlighting the need for more detailed analysis on the actual implications of tanycyte-nutrient sensing and how this process can be modulated, which might allow the discovery of new metabolic and signaling pathways as therapeutic targets, for the treatment of hypothalamic related diseases.
Collapse
Affiliation(s)
- Roberto Javier Elizondo-Vega
- Laboratorio de Biología Celular, Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Antonia Recabal
- Laboratorio de Biología Celular, Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Karina Oyarce
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Concepción, Chile
- *Correspondence: Karina Oyarce
| |
Collapse
|
37
|
Rahman MH, Kim MS, Lee IK, Yu R, Suk K. Interglial Crosstalk in Obesity-Induced Hypothalamic Inflammation. Front Neurosci 2018; 12:939. [PMID: 30618568 PMCID: PMC6300514 DOI: 10.3389/fnins.2018.00939] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 11/29/2018] [Indexed: 12/29/2022] Open
Abstract
Glial cells have recently gained particular attention for their close involvement in neuroinflammation and metabolic disorders including obesity and diabetes. In the central nervous system (CNS), different types of resident glial cells have been documented to express several signaling molecules and related receptors, and their crosstalks have been implicated in physiology and pathology of the CNS. Emerging evidence illustrates that malfunctioning glia and their products are an important component of hypothalamic inflammation. Recent studies have suggested that glia–glia crosstalk is a pivotal mechanism of overnutrition-induced chronic hypothalamic inflammation, which might be intrinsically associated with obesity/diabetes and their pathological consequences. This review covers the recent advances in the molecular aspects of interglial crosstalk in hypothalamic inflammation, proposing a central role of such a crosstalk in the development of obesity, diabetes, and related complications. Finally, we discuss the possibilities and challenges of targeting glial cells and their crosstalk for a better understanding of hypothalamic inflammation and related metabolic dysfunctions.
Collapse
Affiliation(s)
- Md Habibur Rahman
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, School of Medicine, Kyungpook National University, Daegu, South Korea
| | - Min-Seon Kim
- Division of Endocrinology and Metabolism, University of Ulsan College of Medicine, Seoul, South Korea
| | - In-Kyu Lee
- Department of Internal Medicine, Division of Endocrinology and Metabolism, School of Medicine, Kyungpook National University, Daegu, South Korea
| | - Rina Yu
- Department of Food Science and Nutrition, University of Ulsan, Ulsan, South Korea
| | - Kyoungho Suk
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, School of Medicine, Kyungpook National University, Daegu, South Korea
| |
Collapse
|
38
|
Recabal A, Elizondo-Vega R, Philippot C, Salgado M, López S, Palma A, Tarifeño-Saldivia E, Timmermann A, Seifert G, Caprile T, Steinhäuser C, García-Robles MA. Connexin-43 Gap Junctions Are Responsible for the Hypothalamic Tanycyte-Coupled Network. Front Cell Neurosci 2018; 12:406. [PMID: 30534054 PMCID: PMC6275304 DOI: 10.3389/fncel.2018.00406] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 10/19/2018] [Indexed: 12/21/2022] Open
Abstract
Tanycytes are hypothalamic radial glia-like cells that form the basal wall of the third ventricle (3V) where they sense glucose and modulate neighboring neuronal activity to control feeding behavior. This role requires the coupling of hypothalamic cells since transient decreased hypothalamic Cx43 expression inhibits the increase of brain glucose-induced insulin secretion. Tanycytes have been postulated as possible hypothalamic neuronal precursors due to their privileged position in the hypothalamus that allows them to detect mitogenic signals and because they share the markers and characteristics of neuronal precursors located in other neurogenic niches, including the formation of coupled networks through connexins. Using wild-type (WT), Cx30−/– and Cx30−/–, Cx43fl/fl:glial fibrillary acidic protein (GFAP)-Cre (double knockout, dKO) mouse lines, we demonstrated that tanycytes are highly coupled to each other and also give rise to a panglial network specifically through Cx43. Using the human GFAP (hGFAP)-enhanced green fluorescent protein (EGFP) transgenic mouse line, we provided evidence that the main parenchymal-coupled cells were astrocytes. In addition, electrophysiological parameters, such as membrane resistance, were altered when Cx43 was genetically absent or pharmacologically inhibited. Finally, in the dKO mouse line, we detected a significant decrease in the number of hypothalamic proliferative parenchymal cells. Our results demonstrate the importance of Cx43 in tanycyte homotypic and panglial coupling and show that Cx43 function influences the proliferative potential of hypothalamic cells.
Collapse
Affiliation(s)
- Antonia Recabal
- Department of Cellular Biology, Faculty of Biological Sciences, University of Concepcion Concepcion, Chile
| | - Roberto Elizondo-Vega
- Department of Cellular Biology, Faculty of Biological Sciences, University of Concepcion Concepcion, Chile
| | - Camille Philippot
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn Bonn, Germany
| | - Magdiel Salgado
- Department of Cellular Biology, Faculty of Biological Sciences, University of Concepcion Concepcion, Chile
| | - Sergio López
- Department of Cellular Biology, Faculty of Biological Sciences, University of Concepcion Concepcion, Chile
| | - Alejandra Palma
- Department of Cellular Biology, Faculty of Biological Sciences, University of Concepcion Concepcion, Chile
| | - Estefanía Tarifeño-Saldivia
- Department of Biochemistry and Molecular Biology, Faculty of Biological Sciences, University of Concepcion Concepcion, Chile
| | - Aline Timmermann
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn Bonn, Germany
| | - Gerald Seifert
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn Bonn, Germany
| | - Teresa Caprile
- Department of Cellular Biology, Faculty of Biological Sciences, University of Concepcion Concepcion, Chile
| | - Christian Steinhäuser
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn Bonn, Germany
| | | |
Collapse
|
39
|
Abstract
The hypothalamus is the brain region responsible for the maintenance of energetic homeostasis. The regulation of this process arises from the ability of the hypothalamus to orchestrate complex physiological responses such as food intake and energy expenditure, circadian rhythm, stress response, and fertility. Metabolic alterations such as obesity can compromise these hypothalamic regulatory functions. Alterations in circadian rhythm, stress response, and fertility further contribute to aggravate the metabolic dysfunction of obesity and contribute to the development of chronic disorders such as depression and infertility.At cellular level, obesity caused by overnutrition can damage the hypothalamus promoting inflammation and impairing hypothalamic neurogenesis. Furthermore, hypothalamic neurons suffer apoptosis and impairment in synaptic plasticity that can compromise the proper functioning of the hypothalamus. Several factors contribute to these phenomena such as ER stress, oxidative stress, and impairments in autophagy. All these observations occur at the same time and it is still difficult to discern whether inflammatory processes are the main drivers of these cellular dysfunctions or if the hypothalamic hormone resistance (insulin, leptin, and ghrelin) can be pinpointed as the source of several of these events.Understanding the mechanisms that underlie the pathophysiology of obesity in the hypothalamus is crucial for the development of strategies that can prevent or attenuate the deleterious effects of obesity.
Collapse
|
40
|
Alvarsson A, Stanley SA. Remote control of glucose-sensing neurons to analyze glucose metabolism. Am J Physiol Endocrinol Metab 2018; 315:E327-E339. [PMID: 29812985 PMCID: PMC6171010 DOI: 10.1152/ajpendo.00469.2017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 04/25/2018] [Accepted: 05/23/2018] [Indexed: 12/13/2022]
Abstract
The central nervous system relies on a continual supply of glucose, and must be able to detect glucose levels and regulate peripheral organ functions to ensure that its energy requirements are met. Specialized glucose-sensing neurons, first described half a century ago, use glucose as a signal and modulate their firing rates as glucose levels change. Glucose-excited neurons are activated by increasing glucose concentrations, while glucose-inhibited neurons increase their firing rate as glucose concentrations fall and decrease their firing rate as glucose concentrations rise. Glucose-sensing neurons are present in multiple brain regions and are highly expressed in hypothalamic regions, where they are involved in functions related to glucose homeostasis. However, the roles of glucose-sensing neurons in healthy and disease states remain poorly understood. Technologies that can rapidly and reversibly activate or inhibit defined neural populations provide invaluable tools to investigate how specific neural populations regulate metabolism and other physiological roles. Optogenetics has high temporal and spatial resolutions, requires implants for neural stimulation, and is suitable for modulating local neural populations. Chemogenetics, which requires injection of a synthetic ligand, can target both local and widespread populations. Radio- and magnetogenetics offer rapid neural activation in localized or widespread neural populations without the need for implants or injections. These tools will allow us to better understand glucose-sensing neurons and their metabolism-regulating circuits.
Collapse
Affiliation(s)
- Alexandra Alvarsson
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai , New York, New York
| | - Sarah A Stanley
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai , New York, New York
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai , New York, New York
| |
Collapse
|
41
|
Ma Y, Ratnasabapathy R, Izzi-Engbeaya C, Nguyen-Tu MS, Richardson E, Hussain S, De Backer I, Holton C, Norton M, Carrat G, Schwappach B, Rutter GA, Dhillo WS, Gardiner J. Hypothalamic arcuate nucleus glucokinase regulates insulin secretion and glucose homeostasis. Diabetes Obes Metab 2018; 20:2246-2254. [PMID: 29748994 PMCID: PMC6099255 DOI: 10.1111/dom.13359] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 04/30/2018] [Accepted: 05/09/2018] [Indexed: 01/08/2023]
Abstract
AIMS To investigate the role of arcuate glucokinase (GK) in the regulation of glucose homeostasis. MATERIALS AND METHODS A recombinant adeno-associated virus expressing either GK or an antisense GK construct was used to alter GK activity specifically in the hypothalamic arcuate nucleus (arc). GK activity in this nucleus was also increased by stereotactic injection of the GK activator, compound A. The effect of altered arc GK activity on glucose homeostasis was subsequently investigated using glucose and insulin tolerance tests. RESULTS Increased GK activity specifically within the arc increased insulin secretion and improved glucose tolerance in rats during oral glucose tolerance tests. Decreased GK activity in this nucleus reduced insulin secretion and increased glucose levels during the same tests. Insulin sensitivity was not affected in either case. The effect of arc GK was maintained in a model of type 2 diabetes. CONCLUSIONS These results demonstrate a role for arc GK in systemic glucose homeostasis.
Collapse
Affiliation(s)
- Yue Ma
- Section of Endocrinology and Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Risheka Ratnasabapathy
- Section of Endocrinology and Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Chioma Izzi-Engbeaya
- Section of Endocrinology and Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Marie-Sophie Nguyen-Tu
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Errol Richardson
- Section of Endocrinology and Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Sufyan Hussain
- Section of Endocrinology and Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Ivan De Backer
- Section of Endocrinology and Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Christopher Holton
- Section of Endocrinology and Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Mariana Norton
- Section of Endocrinology and Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Gaelle Carrat
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Blanche Schwappach
- Department of Molecular Biology, Centre for Biochemistry and Molecular Cell Biology, Heart Research Centre Göttingen, University Medicine Göttingen, Göttingen, Germany
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Waljit S Dhillo
- Section of Endocrinology and Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - James Gardiner
- Section of Endocrinology and Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| |
Collapse
|
42
|
Gasser PJ, Lowry CA. Organic cation transporter 3: A cellular mechanism underlying rapid, non-genomic glucocorticoid regulation of monoaminergic neurotransmission, physiology, and behavior. Horm Behav 2018; 104:173-182. [PMID: 29738736 PMCID: PMC7137088 DOI: 10.1016/j.yhbeh.2018.05.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 05/02/2018] [Accepted: 05/03/2018] [Indexed: 01/11/2023]
Abstract
Contribution to Special Issue on Fast effects of steroids. Corticosteroid hormones act at intracellular glucocorticoid receptors (GR) and mineralocorticoid receptors (MR) to alter gene expression, leading to diverse physiological and behavioral responses. In addition to these classical genomic effects, corticosteroid hormones also exert rapid actions on physiology and behavior through a variety of non-genomic mechanisms, some of which involve GR or MR, and others of which are independent of these receptors. One such GR-independent mechanism involves corticosteroid-induced inhibition of monoamine transport mediated by "uptake2" transporters, including organic cation transporter 3 (OCT3), a low-affinity, high-capacity transporter for norepinephrine, epinephrine, dopamine, serotonin and histamine. Corticosterone directly and acutely inhibits OCT3-mediated transport. This review describes the studies that initially characterized uptake2 processes in peripheral tissues, and outlines studies that demonstrated OCT3 expression and corticosterone-sensitive monoamine transport in the brain. Evidence is presented supporting the hypothesis that corticosterone can exert rapid, GR-independent actions on neuronal physiology and behavior by inhibiting OCT3-mediated monoamine clearance. Implications of this mechanism for glucocorticoid-monoamine interactions in the context-dependent regulation of behavior are discussed.
Collapse
Affiliation(s)
- Paul J Gasser
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI 53201, USA.
| | - Christopher A Lowry
- Department of Integrative Physiology and Center for Neuroscience, University of Colorado Boulder, Boulder, CO 80309, USA; Department of Physical Medicine and Rehabilitation, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Rocky Mountain Mental Illness Research Education and Clinical Center (MIRECC), Denver Veterans Affairs Medical Center (VAMC), Denver, CO 80220, USA; Military and Veteran Microbiome Consortium for Research and Education (MVM-CoRE), Denver, CO 80220, USA.
| |
Collapse
|
43
|
Cavalcanti-de-Albuquerque JP, Kincheski GC, Louzada RA, Galina A, Pierucci APTR, Carvalho DP. Intense physical exercise potentiates glucose inhibitory effect over food intake of male Wistar rats. Exp Physiol 2018; 103:1076-1086. [PMID: 29893447 DOI: 10.1113/ep086916] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 06/06/2018] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? How does an acute session of exercise affect food intake of male Wistar rats? What is the main finding and its importance? Food intake in male Wistar rats is decreased in the first hour after physical exercise independent of the intensity. Moreover, high-intensity exercise potentiates the anorexic effect of peripheral glucose administration. This work raises new feeding-related targets that would explain how exercise drives body weight loss. ABSTRACT Obesity has emerged as a critical metabolic disorder in modern society. An adequate lifestyle with a well-oriented programme of diet and physical exercise (PE) can prevent or potentially even cure obesity. Additionally, PE might lead to weight loss by increasing energy expenditure and decreasing hunger perception. In this article, we hypothesize that an acute exercise session would potentiate the glucose inhibitory effects on food intake in male Wistar rats. Our data show that moderate- or high-intensity PE significantly decreased food intake, although no changes in the expression of feeding-related neuropeptide in the arcuate nucleus of the hypothalamus were found. Exercised animals demonstrated a reduced glucose tolerance and increased blood insulin concentration. Intraperitoneal administration of glucose decreased food intake in control animals. In the animals submitted to moderate-intensity PE, the decrease in food intake promoted by glucose was similar to controls; however, an interaction was observed when glucose was injected in the high-intensity PE group, in which food intake was significantly lower than the effect produced by glucose alone. A different pattern of expression was observed for the monocarboxylate transporter isoforms (MCT1, 2 and 4) and 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFBP3) in the hypothalamus, which was dependent on the exercise intensity. In conclusion, PE decreases food intake independently of the intensity. However, an interaction between PE and the anorexic effect of glucose is only observed when a high-intensity exercise is performed. These data show an essential role of exercise intensity in the modulation of the glucose inhibitory effect on food intake.
Collapse
Affiliation(s)
- João Paulo Cavalcanti-de-Albuquerque
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,Institute of Nutrition Josue de Castro, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Grasielle Clotildes Kincheski
- Institute of Medical Biochemistry Leopoldo De Meis, Federal University of Rio de Janeiro, Center of Health Science, Rio de Janeiro, Brazil
| | - Ruy Andrade Louzada
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Antônio Galina
- Institute of Medical Biochemistry Leopoldo De Meis, Federal University of Rio de Janeiro, Center of Health Science, Rio de Janeiro, Brazil
| | | | - Denise P Carvalho
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| |
Collapse
|
44
|
Prevot V, Dehouck B, Sharif A, Ciofi P, Giacobini P, Clasadonte J. The Versatile Tanycyte: A Hypothalamic Integrator of Reproduction and Energy Metabolism. Endocr Rev 2018; 39:333-368. [PMID: 29351662 DOI: 10.1210/er.2017-00235] [Citation(s) in RCA: 139] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 01/12/2018] [Indexed: 12/16/2022]
Abstract
The fertility and survival of an individual rely on the ability of the periphery to promptly, effectively, and reproducibly communicate with brain neural networks that control reproduction, food intake, and energy homeostasis. Tanycytes, a specialized glial cell type lining the wall of the third ventricle in the median eminence of the hypothalamus, appear to act as the linchpin of these processes by dynamically controlling the secretion of neuropeptides into the portal vasculature by hypothalamic neurons and regulating blood-brain and blood-cerebrospinal fluid exchanges, both processes that depend on the ability of these cells to adapt their morphology to the physiological state of the individual. In addition to their barrier properties, tanycytes possess the ability to sense blood glucose levels, and play a fundamental and active role in shuttling circulating metabolic signals to hypothalamic neurons that control food intake. Moreover, accumulating data suggest that, in keeping with their putative descent from radial glial cells, tanycytes are endowed with neural stem cell properties and may respond to dietary or reproductive cues by modulating hypothalamic neurogenesis. Tanycytes could thus constitute the missing link in the loop connecting behavior, hormonal changes, signal transduction, central neuronal activation and, finally, behavior again. In this article, we will examine these recent advances in the understanding of tanycytic plasticity and function in the hypothalamus and the underlying molecular mechanisms. We will also discuss the putative involvement and therapeutic potential of hypothalamic tanycytes in metabolic and fertility disorders.
Collapse
Affiliation(s)
- Vincent Prevot
- Inserm, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Jean-Pierre Aubert Research Center, Lille, France.,University of Lille, FHU 1000 Days for Health, School of Medicine, Lille, France
| | - Bénédicte Dehouck
- Inserm, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Jean-Pierre Aubert Research Center, Lille, France.,University of Lille, FHU 1000 Days for Health, School of Medicine, Lille, France
| | - Ariane Sharif
- Inserm, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Jean-Pierre Aubert Research Center, Lille, France.,University of Lille, FHU 1000 Days for Health, School of Medicine, Lille, France
| | - Philippe Ciofi
- Inserm, Neurocentre Magendie, Bordeaux, France.,Université de Bordeaux, Bordeaux, France
| | - Paolo Giacobini
- Inserm, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Jean-Pierre Aubert Research Center, Lille, France.,University of Lille, FHU 1000 Days for Health, School of Medicine, Lille, France
| | - Jerome Clasadonte
- Inserm, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Jean-Pierre Aubert Research Center, Lille, France.,University of Lille, FHU 1000 Days for Health, School of Medicine, Lille, France
| |
Collapse
|
45
|
Endocannabinoids in Body Weight Control. Pharmaceuticals (Basel) 2018; 11:ph11020055. [PMID: 29849009 PMCID: PMC6027162 DOI: 10.3390/ph11020055] [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] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 05/17/2018] [Accepted: 05/28/2018] [Indexed: 12/15/2022] Open
Abstract
Maintenance of body weight is fundamental to maintain one's health and to promote longevity. Nevertheless, it appears that the global obesity epidemic is still constantly increasing. Endocannabinoids (eCBs) are lipid messengers that are involved in overall body weight control by interfering with manifold central and peripheral regulatory circuits that orchestrate energy homeostasis. Initially, blocking of eCB signaling by first generation cannabinoid type 1 receptor (CB1) inverse agonists such as rimonabant revealed body weight-reducing effects in laboratory animals and men. Unfortunately, rimonabant also induced severe psychiatric side effects. At this point, it became clear that future cannabinoid research has to decipher more precisely the underlying central and peripheral mechanisms behind eCB-driven control of feeding behavior and whole body energy metabolism. Here, we will summarize the most recent advances in understanding how central eCBs interfere with circuits in the brain that control food intake and energy expenditure. Next, we will focus on how peripheral eCBs affect food digestion, nutrient transformation and energy expenditure by interfering with signaling cascades in the gastrointestinal tract, liver, pancreas, fat depots and endocrine glands. To finally outline the safe future potential of cannabinoids as medicines, our overall goal is to address the molecular, cellular and pharmacological logic behind central and peripheral eCB-mediated body weight control, and to figure out how these precise mechanistic insights are currently transferred into the development of next generation cannabinoid medicines displaying clearly improved safety profiles, such as significantly reduced side effects.
Collapse
|
46
|
Erickson MA, Banks WA. Neuroimmune Axes of the Blood-Brain Barriers and Blood-Brain Interfaces: Bases for Physiological Regulation, Disease States, and Pharmacological Interventions. Pharmacol Rev 2018; 70:278-314. [PMID: 29496890 PMCID: PMC5833009 DOI: 10.1124/pr.117.014647] [Citation(s) in RCA: 192] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Central nervous system (CNS) barriers predominantly mediate the immune-privileged status of the brain, and are also important regulators of neuroimmune communication. It is increasingly appreciated that communication between the brain and immune system contributes to physiologic processes, adaptive responses, and disease states. In this review, we discuss the highly specialized features of brain barriers that regulate neuroimmune communication in health and disease. In section I, we discuss the concept of immune privilege, provide working definitions of brain barriers, and outline the historical work that contributed to the understanding of CNS barrier functions. In section II, we discuss the unique anatomic, cellular, and molecular characteristics of the vascular blood-brain barrier (BBB), blood-cerebrospinal fluid barrier, and tanycytic barriers that confer their functions as neuroimmune interfaces. In section III, we consider BBB-mediated neuroimmune functions and interactions categorized as five neuroimmune axes: disruption, responses to immune stimuli, uptake and transport of immunoactive substances, immune cell trafficking, and secretions of immunoactive substances. In section IV, we discuss neuroimmune functions of CNS barriers in physiologic and disease states, as well as pharmacological interventions for CNS diseases. Throughout this review, we highlight many recent advances that have contributed to the modern understanding of CNS barriers and their interface functions.
Collapse
Affiliation(s)
- Michelle A Erickson
- Geriatric Research and Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington; and Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington, Seattle, Washington
| | - William A Banks
- Geriatric Research and Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington; and Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington, Seattle, Washington
| |
Collapse
|
47
|
Ebling FJP, Lewis JE. Tanycytes and hypothalamic control of energy metabolism. Glia 2018; 66:1176-1184. [DOI: 10.1002/glia.23303] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 12/21/2017] [Accepted: 01/23/2018] [Indexed: 01/15/2023]
Affiliation(s)
- Francis J. P. Ebling
- School of Life Sciences; University of Nottingham Medical School, Queen's Medical Centre; Nottingham NG7 2UH United Kingdom
| | - Jo E. Lewis
- School of Life Sciences; University of Nottingham Medical School, Queen's Medical Centre; Nottingham NG7 2UH United Kingdom
| |
Collapse
|
48
|
Zhou YD. Glial Regulation of Energy Metabolism. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1090:105-121. [DOI: 10.1007/978-981-13-1286-1_6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|
49
|
Barahona MJ, Llanos P, Recabal A, Escobar-Acuña K, Elizondo-Vega R, Salgado M, Ordenes P, Uribe E, Sepúlveda FJ, Araneda RC, García-Robles MA. Glial hypothalamic inhibition of GLUT2 expression alters satiety, impacting eating behavior. Glia 2017; 66:592-605. [PMID: 29178321 PMCID: PMC5814884 DOI: 10.1002/glia.23267] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 10/31/2017] [Accepted: 11/07/2017] [Indexed: 12/22/2022]
Abstract
Glucose is a key modulator of feeding behavior. By acting in peripheral tissues and in the central nervous system, it directly controls the secretion of hormones and neuropeptides and modulates the activity of the autonomic nervous system. GLUT2 is required for several glucoregulatory responses in the brain, including feeding behavior, and is localized in the hypothalamus and brainstem, which are the main centers that control this behavior. In the hypothalamus, GLUT2 has been detected in glial cells, known as tanycytes, which line the basal walls of the third ventricle (3V). This study aimed to clarify the role of GLUT2 expression in tanycytes in feeding behavior using 3V injections of an adenovirus encoding a shRNA against GLUT2 and the reporter EGFP (Ad‐shGLUT2). Efficient in vivo GLUT2 knockdown in rat hypothalamic tissue was demonstrated by qPCR and Western blot analyses. Specificity of cell transduction in the hypothalamus and brainstem was evaluated by EGFP‐fluorescence and immunohistochemistry, which showed EGFP expression specifically in ependymal cells, including tanycytes. The altered mRNA levels of both orexigenic and anorexigenic neuropeptides suggested a loss of response to increased glucose in the 3V. Feeding behavior analysis in the fasting‐feeding transition revealed that GLUT2‐knockdown rats had increased food intake and body weight, suggesting an inhibitory effect on satiety. Taken together, suppression of GLUT2 expression in tanycytes disrupted the hypothalamic glucosensing mechanism, which altered the feeding behavior.
Collapse
Affiliation(s)
- María J Barahona
- Laboratorio de Biología Celular, Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Paula Llanos
- Laboratorio de Biología Celular, Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Antonia Recabal
- Laboratorio de Biología Celular, Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Kathleen Escobar-Acuña
- Laboratorio de Biología Celular, Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Roberto Elizondo-Vega
- Laboratorio de Biología Celular, Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile.,Laboratorio de Inmunología Celular y Molecular, Centro de Investigación Biomédica, Facultad de Medicina, Universidad de los Andes, Santiago, Chile
| | - Magdiel Salgado
- Laboratorio de Biología Celular, Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Patricio Ordenes
- Laboratorio de Biología Celular, Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Elena Uribe
- Departamento de Bioquímica y Biología Molecular, Universidad de Concepción, Chile
| | - Fernando J Sepúlveda
- Departamento de Bioquímica y Biología Molecular, Universidad de Concepción, Chile.,Departamento de Ciencias Biológica Universidad Andrés Bello, Concepción, Chile
| | - Ricardo C Araneda
- Department of Biology, University of Maryland, College Park, Maryland
| | - María A García-Robles
- Laboratorio de Biología Celular, Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| |
Collapse
|
50
|
Pouchain Ribeiro Neto R, Clarke IJ, Conductier G. Alteration in the relationship between tanycytes and gonadotrophin-releasing hormone neurosecretory terminals following long-term metabolic manipulation in the sheep. J Neuroendocrinol 2017; 29. [PMID: 28722251 DOI: 10.1111/jne.12509] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 07/13/2017] [Accepted: 07/14/2017] [Indexed: 12/30/2022]
Abstract
The activity of the hypothalamic-pituitary gonadal axis is influenced by energy reserves, such that an increase or a decrease in adiposity may perturb the secretion and action of gonadotrophin-releasing hormone (GnRH). This is considered to be a result of the signalling of hormones such as leptin, which act upon neuronal systems controlling GnRH secretion. Other work shows plasticity in the relationship between tanycytes and GnRH neurosecretory terminals in the median eminence across the oestrous cycle and we hypothesised that a similar plasticity may occur with altered metabolic status. We studied Lean, Normal and Fat ovariectomised ewes, which displayed differences in gonadotrophin status, and investigated the relationship between tanycytes and GnRH neuroterminals. Under both Lean and Fat conditions, an altered anatomical arrangement between these two elements was observed in the vicinity of the blood vessels of the primary plexus of the hypophysial portal blood system. These data suggest that such plasticity is an important determinant of the rate of secretion of GnRH in animals of differing metabolic status and that this also contributes to the relative hypogonadotrophic condition prevailing with metabolic extremes.
Collapse
Affiliation(s)
- R Pouchain Ribeiro Neto
- Department of Physiology, Monash University, Melbourne, Victoria, Australia
- Neuroscience Program, Monash Biomedicine Discovery Institute, Department of Physiology, Monash University, Melbourne, Victoria, Australia
| | - I J Clarke
- Department of Physiology, Monash University, Melbourne, Victoria, Australia
- Neuroscience Program, Monash Biomedicine Discovery Institute, Department of Physiology, Monash University, Melbourne, Victoria, Australia
| | - G Conductier
- Department of Physiology, Monash University, Melbourne, Victoria, Australia
- Neuroscience Program, Monash Biomedicine Discovery Institute, Department of Physiology, Monash University, Melbourne, Victoria, Australia
| |
Collapse
|