1
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Appenroth D, Cázarez-Márquez F. Seasonal food intake and energy balance: Neuronal and non-neuronal control mechanisms. Neuropharmacology 2024; 257:110050. [PMID: 38914372 DOI: 10.1016/j.neuropharm.2024.110050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 06/05/2024] [Accepted: 06/21/2024] [Indexed: 06/26/2024]
Abstract
Animals inhabiting temperate and high latitudes undergo drastic seasonal changes in energy storage, facilitated by changes in food intake and body mass. Those seasonal changes in the animal's biology are not mere consequences of environmental energy availability but are anticipatory responses to the energetic requirements of the upcoming season and are actively timed by tracking the annual progression in photoperiod. In this review, we discuss how photoperiod is used to control energy balance seasonally and how this is distinct from energy homeostasis. Most notably, we suggest that photoperiodic control of food intake and body mass does not originate from the arcuate nucleus, as for homeostatic appetite control, but is rather to be found in hypothalamic tanycytes. Tanycytes are specialized ependymal cells lining the third ventricle, which can sense metabolites from the cerebrospinal fluid (e.g. glucose) and can control access of circulating signals to the brain. They are also essential in conveying time-of-year information by integrating photoperiod and altering hypothalamic thyroid metabolism, a feature that is conserved in seasonal vertebrates and connects to seasonal breeding and metabolism. We also discuss how homeostatic feedback signals are handled during times of rapid energetic transitions. Studies on leptin in seasonal mammals suggest a seasonal shift in central sensitivity and blood-brain transport, which might be facilitated by tanycytes.
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Affiliation(s)
- Daniel Appenroth
- Arctic Seasonal Timekeeping Initiative (ASTI), Arctic Chronobiology & Physiology, Arctic & Marine Biology, BFE, UiT - Arctic University of Norway, Tromsø, Norway.
| | - Fernando Cázarez-Márquez
- Arctic Seasonal Timekeeping Initiative (ASTI), Arctic Chronobiology & Physiology, Arctic & Marine Biology, BFE, UiT - Arctic University of Norway, Tromsø, Norway
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2
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Zhou S, Makashova O, Chevillard PM, Josey V, Li B, Prager-Khoutorsky M. Constitutive cell proliferation and neurogenesis in the organum vasculosum lamina terminalis and subfornical organ of adult rats. J Neuroendocrinol 2024; 36:e13377. [PMID: 38418229 DOI: 10.1111/jne.13377] [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: 10/14/2023] [Revised: 02/08/2024] [Accepted: 02/09/2024] [Indexed: 03/01/2024]
Abstract
Neurogenesis continues throughout adulthood in the subventricular zone, hippocampal subgranular zone, and the hypothalamic median eminence (ME) and the adjacent medio-basal hypothalamus. The ME is one of the circumventricular organs (CVO), which are specialized brain areas characterized by an incomplete blood-brain barrier and, thus, are involved in mediating communication between the central nervous system and the periphery. Additional CVOs include the organum vasculosum laminae terminalis (OVLT) and the subfornical organs (SFO). Previous studies have demonstrated that the ME contains neural stem cells (NSCs) capable of generating new neurons and glia in the adult brain. However, it remains unclear whether the OVLT and SFO also contain proliferating cells, the identity of these cells, and their ability to differentiate into mature neurons. Here we show that glial and mural subtypes exhibit NSC characteristics, expressing the endogenous mitotic maker Ki67, and incorporating the exogenous mitotic marker BrdU in the OVLT and SFO of adult rats. Glial cells constitutively proliferating in the SFO comprise NG2 glia, while in the OVLT, both NG2 glia and tanycytes appear to constitute the NSC pool. Furthermore, pericytes, which are mural cells associated with capillaries, also contribute to the pool of cells constitutively proliferating in the OVLT and SFO of adult rats. In addition to these glial and mural cells, a fraction of NSCs containing proliferation markers Ki67 and BrdU also expresses the early postmitotic neuronal marker doublecortin, suggesting that these CVOs comprise newborn neurons. Notably, these neurons can differentiate and express the mature neuronal marker NeuN. These findings establish the sensory CVOs OVLT and SFO as additional neurogenic niches, where the generation of new neurons and glia persists in the adult brain.
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Affiliation(s)
- Suijian Zhou
- Department of Physiology, McIntyre Medical Sciences Building, McGill University, Montreal, Québec, Canada
| | - Olena Makashova
- Department of Physiology, McIntyre Medical Sciences Building, McGill University, Montreal, Québec, Canada
| | - Pierre-Marie Chevillard
- Department of Physiology, McIntyre Medical Sciences Building, McGill University, Montreal, Québec, Canada
| | - Vanessa Josey
- Department of Physiology, McIntyre Medical Sciences Building, McGill University, Montreal, Québec, Canada
| | - Banruo Li
- Department of Physiology, McIntyre Medical Sciences Building, McGill University, Montreal, Québec, Canada
| | - Masha Prager-Khoutorsky
- Department of Physiology, McIntyre Medical Sciences Building, McGill University, Montreal, Québec, Canada
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3
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Rivagorda M, Prevot V, Schwaninger M. Seasonal biology: Tanycytes give the hypothalamus a spring makeover. Curr Biol 2024; 34:R209-R211. [PMID: 38471452 DOI: 10.1016/j.cub.2024.01.055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2024]
Abstract
In many species, metabolic and reproductive functions are coupled to the seasons. Tanycytes, specialized glial cells in the hypothalamus, play an important function in these physiological changes. A new study now shows that light exposure drastically alters the formation of sensory cilia on tanycytes.
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Affiliation(s)
- Manon Rivagorda
- Institute of Experimental and Clinical Pharmacology and Toxicology, Center of Brain, Behavior and Metabolism, University of Lübeck, Lübeck, Germany
| | - Vincent Prevot
- Inserm, CHU Lille, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Lille Neuroscience and Cognition, Université de Lille, Lille, France
| | - Markus Schwaninger
- Institute of Experimental and Clinical Pharmacology and Toxicology, Center of Brain, Behavior and Metabolism, University of Lübeck, Lübeck, Germany.
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4
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Lei Y, Liang X, Sun Y, Yao T, Gong H, Chen Z, Gao Y, Wang H, Wang R, Huang Y, Yang T, Yu M, Liu L, Yi CX, Wu QF, Kong X, Xu X, Liu S, Zhang Z, Liu T. Region-specific transcriptomic responses to obesity and diabetes in macaque hypothalamus. Cell Metab 2024; 36:438-453.e6. [PMID: 38325338 DOI: 10.1016/j.cmet.2024.01.003] [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: 06/08/2023] [Revised: 10/27/2023] [Accepted: 01/05/2024] [Indexed: 02/09/2024]
Abstract
The hypothalamus plays a crucial role in the progression of obesity and diabetes; however, its structural complexity and cellular heterogeneity impede targeted treatments. Here, we profiled the single-cell and spatial transcriptome of the hypothalamus in obese and sporadic type 2 diabetic macaques, revealing primate-specific distributions of clusters and genes as well as spatial region, cell-type-, and gene-feature-specific changes. The infundibular (INF) and paraventricular nuclei (PVN) are most susceptible to metabolic disruption, with the PVN being more sensitive to diabetes. In the INF, obesity results in reduced synaptic plasticity and energy sensing capability, whereas diabetes involves molecular reprogramming associated with impaired tanycytic barriers, activated microglia, and neuronal inflammatory response. In the PVN, cellular metabolism and neural activity are suppressed in diabetic macaques. Spatial transcriptomic data reveal microglia's preference for the parenchyma over the third ventricle in diabetes. Our findings provide a comprehensive view of molecular changes associated with obesity and diabetes.
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Affiliation(s)
- Ying Lei
- BGI-Research, Hangzhou 310012, China; BGI-Research, Shenzhen 518103, China
| | - Xian Liang
- State Key Laboratory of Genetic Engineering, Department of Endocrinology and Metabolism, Human Phenome Institute, Institute of Metabolism and Integrative Biology, and School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai 200438, China; School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Yunong Sun
- BGI-Research, Hangzhou 310012, China; BGI-Research, Shenzhen 518103, China
| | - Ting Yao
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University School of Medicine, Xi'an, Shanxi 710063, China
| | - Hongyu Gong
- School of Life Sciences, Institues of Biomedical Sciences, Inner Mongolia University, Hohhot 010000, China
| | - Zhenhua Chen
- State Key Laboratory of Molecular Development Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yuanqing Gao
- Jiangsu Provincial Key Laboratory of Cardiovascular and Cerebrovascular Medicine, School of Pharmacy, Nanjing Medical University, Nanjing 211166, China
| | - Hui Wang
- School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Ru Wang
- School of Kinesiology, Shanghai University of Sport, Shanghai 200438, China
| | - Yunqi Huang
- BGI-Research, Hangzhou 310012, China; BGI-Research, Shenzhen 518103, China
| | - Tao Yang
- China National GeneBank, BGI-Shenzhen, Shenzhen 518120, China
| | - Miao Yu
- School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Longqi Liu
- BGI-Research, Hangzhou 310012, China; BGI-Research, Shenzhen 518103, China
| | - Chun-Xia Yi
- Department of Endocrinology and Metabolism, Amsterdam University Medical Centers, University of Amsterdam, Meibergdreef 9, 1105AZ Amsterdam, the Netherlands
| | - Qing-Feng Wu
- State Key Laboratory of Molecular Development Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xingxing Kong
- School of Life Sciences, Fudan University, Shanghai 200438, China.
| | - Xun Xu
- BGI-Research, Hangzhou 310012, China; BGI-Research, Shenzhen 518103, China.
| | - Shiping Liu
- BGI-Research, Hangzhou 310012, China; BGI-Research, Shenzhen 518103, China.
| | - Zhi Zhang
- State Key Laboratory of Genetic Engineering, Department of Endocrinology and Metabolism, Human Phenome Institute, Institute of Metabolism and Integrative Biology, and School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai 200438, China; School of Life Sciences, Fudan University, Shanghai 200438, China.
| | - Tiemin Liu
- State Key Laboratory of Genetic Engineering, Department of Endocrinology and Metabolism, Human Phenome Institute, Institute of Metabolism and Integrative Biology, and School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai 200438, China; School of Life Sciences, Fudan University, Shanghai 200438, China; School of Life Sciences, Institues of Biomedical Sciences, Inner Mongolia University, Hohhot 010000, China.
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5
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Chandrasekar A, Schmidtlein PM, Neve V, Rivagorda M, Spiecker F, Gauthier K, Prevot V, Schwaninger M, Müller-Fielitz H. Regulation of Thyroid Hormone Gatekeepers by Thyrotropin in Tanycytes. Thyroid 2024; 34:261-273. [PMID: 38115594 DOI: 10.1089/thy.2023.0375] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
Background: Tanycytes are specialized glial cells within the mediobasal hypothalamus that have multiple functions, including hormone sensing and regulation of hypophysiotropic hormone secretion. There are ongoing discussions about the role of tanycytes in regulating the supply of hypothalamic thyroid hormones (THs) through the expression of TH transporters (Slc16a2, Slco1c1) and deiodinases (Dio2, Dio3). In this study, we investigated the potential feedback effect of thyrotropin (TSH) on the transcription of these gatekeeper genes on tanycytes. Methods: We analyzed the changes in the expression of TH-gatekeeper genes, in TSH-stimulated primary tanycytes, using quantitative polymerase chain reaction (qPCR). We also used RNAScope® in brain slices to further reveal the local distribution of the transcripts. In addition, we blocked intracellular pathways and used small-interfering RNA (siRNA) to elucidate differences in the regulation of the gatekeeper genes. Results: TSH elevated messenger RNA (mRNA) levels of Slco1c1, Dio2, and Dio3 in tanycytes, while Slc16a2 was mostly unaffected. Blockade and knockdown of the TSH receptor (TSHR) and antagonization of cAMP response element-binding protein (CREB) clearly abolished the increased expression induced by TSH, indicating PKA-dependent regulation through the TSHR. The TSH-dependent expression of Dio3 and Slco1c1 was also regulated by protein kinase C (PKC), and in case of Dio3, also by extracellular signal-regulated kinase (ERK) activity. Importantly, these gene regulations were specifically found in different subpopulations of tanycytes. Conclusions: This study demonstrates that TSH induces transcriptional regulation of TH-gatekeeper genes in tanycytes through the Tshr/Gαq/PKC pathway, in parallel to the Tshr/Gαs/PKA/CREB pathway. These differential actions of TSH on tanycytic subpopulations appear to be important for coordinating the supply of TH to the hypothalamus and aid its functions.
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Affiliation(s)
- Akila Chandrasekar
- Institute for Experimental and Clinical Pharmacology and Toxicology, Center of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
| | - Paula Marie Schmidtlein
- Institute for Experimental and Clinical Pharmacology and Toxicology, Center of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
| | - Vanessa Neve
- Institute for Experimental and Clinical Pharmacology and Toxicology, Center of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
| | - Manon Rivagorda
- Institute for Experimental and Clinical Pharmacology and Toxicology, Center of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
| | - Frauke Spiecker
- Institute for Experimental and Clinical Pharmacology and Toxicology, Center of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
| | - Karine Gauthier
- ENS de Lyon, INRAE, CNRS, Institut de Génomique Fonctionnelle de Lyon, University of Lyon, Lyon, France
| | - Vincent Prevot
- Inserm, CHU Lille, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Lille Neuroscience & Cognition, UMR-S 1172, European Genomic Institute for Diabetes (EGID), University of Lille, Lille, France
| | - Markus Schwaninger
- Institute for Experimental and Clinical Pharmacology and Toxicology, Center of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
- DZHK (German Research Centre for Cardiovascular Research), Hamburg-Lübeck-Kiel, Lübeck, Germany
| | - Helge Müller-Fielitz
- Institute for Experimental and Clinical Pharmacology and Toxicology, Center of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
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6
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Prévot V, Duittoz A. A role for GnRH in olfaction and cognition: Implications for veterinary medicine. Reprod Domest Anim 2023; 58 Suppl 2:109-124. [PMID: 37329313 DOI: 10.1111/rda.14411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 06/05/2023] [Accepted: 06/14/2023] [Indexed: 06/19/2023]
Abstract
Pulsatile secretion of gonadotropin-releasing hormone (GnRH) is essential for the activation and maintenance of the function of the hypothalamic-pituitary-gonadal (HPG) axis, which controls the onset of puberty and fertility. Two provocative recent studies suggest that, in addition to control reproduction, the neurons in the brain that produce GnRH are also involved in the control postnatal brain maturation, odour discrimination and adult cognition. Long-acting GnRH antagonists and agonists are commonly used to control fertility and behaviour in veterinary medicine, primarily in males. This review puts into perspective the potential risks of these androgen deprivation therapies and immunization on olfactory and cognitive performances and well-aging in domestic animals, including pets. We will also discuss the results reporting beneficial effects of pharmacological interventions restoring physiological GnRH levels on olfactory and cognitive alterations in preclinical models of Alzheimer's disease, which shares many pathophysiological and behavioural hallmarks with canine cognitive dysfunction. These novel findings raise the intriguing possibility that pulsatile GnRH therapy holds therapeutic potential for the management of this behavioural syndrome affecting older dogs.
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Affiliation(s)
- Vincent Prévot
- Univ. Lille, Inserm, CHU Lille, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Lille Neuroscience & Cognition, UMR_S1172, Lille, France
| | - Anne Duittoz
- Physiologie de la Reproduction et des Comportements (PRC) UMR7247 INRA, CNRS, Centre INRAE Val de Loire, IFCE, Université de Tours, Nouzilly, France
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7
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Boer GA, Hay DL, Tups A. Obesity pharmacotherapy: incretin action in the central nervous system. Trends Pharmacol Sci 2023; 44:50-63. [PMID: 36462999 DOI: 10.1016/j.tips.2022.11.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 11/02/2022] [Accepted: 11/08/2022] [Indexed: 12/02/2022]
Abstract
The prevalence of obesity is rising, creating an urgent need for efficacious therapies. Recent clinical trials show that tirzepatide, a dual agonist of receptors for the incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), yields more weight loss than selective GLP-1 receptor (GLP-1R) agonists. Incretin receptors in the central nervous system (CNS) may contribute to these effects. Yet exactly how each receptor regulates body weight from within the CNS is not clearly understood. It remains especially unclear how GIP receptor (GIPR) signalling contributes to the effects of tirzepatide because both stimulation and inhibition of CNS GIPRs yield weight loss in preclinical models. We summarise current knowledge on CNS incretin receptor pharmacology to provide insight into the potential mechanisms of action of dual GIPR/GLP-1R agonists, with tirzepatide as the exemplar. In addition, we discuss recent developments in incretin-based dual- and tri-agonism for inducing weight loss in obese individuals.
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Affiliation(s)
- Geke Aline Boer
- Centre for Neuroendocrinology, Department of Physiology, University of Otago, Otago, New Zealand
| | - Debbie L Hay
- Department of Pharmacology and Toxicology, University of Otago, Otago, New Zealand; Maurice Wilkins Centre, Auckland, New Zealand
| | - Alexander Tups
- Centre for Neuroendocrinology, Department of Physiology, University of Otago, Otago, New Zealand; Maurice Wilkins Centre, Auckland, New Zealand.
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8
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Tanycytes control hypothalamic liraglutide uptake and its anti-obesity actions. Cell Metab 2022; 34:1054-1063.e7. [PMID: 35716660 PMCID: PMC7613793 DOI: 10.1016/j.cmet.2022.06.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 08/08/2021] [Accepted: 06/01/2022] [Indexed: 11/24/2022]
Abstract
Liraglutide, an anti-diabetic drug and agonist of the glucagon-like peptide one receptor (GLP1R), has recently been approved to treat obesity in individuals with or without type 2 diabetes. Despite its extensive metabolic benefits, the mechanism and site of action of liraglutide remain unclear. Here, we demonstrate that liraglutide is shuttled to target cells in the mouse hypothalamus by specialized ependymoglial cells called tanycytes, bypassing the blood-brain barrier. Selectively silencing GLP1R in tanycytes or inhibiting tanycytic transcytosis by botulinum neurotoxin expression not only hampers liraglutide transport into the brain and its activation of target hypothalamic neurons, but also blocks its anti-obesity effects on food intake, body weight and fat mass, and fatty acid oxidation. Collectively, these striking data indicate that the liraglutide-induced activation of hypothalamic neurons and its downstream metabolic effects are mediated by its tanycytic transport into the mediobasal hypothalamus, strengthening the notion of tanycytes as key regulators of metabolic homeostasis.
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9
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Nampoothiri S, Nogueiras R, Schwaninger M, Prevot V. Glial cells as integrators of peripheral and central signals in the regulation of energy homeostasis. Nat Metab 2022; 4:813-825. [PMID: 35879459 PMCID: PMC7613794 DOI: 10.1038/s42255-022-00610-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 06/15/2022] [Indexed: 01/03/2023]
Abstract
Communication between the periphery and the brain is key for maintaining energy homeostasis. To do so, peripheral signals from the circulation reach the brain via the circumventricular organs (CVOs), which are characterized by fenestrated vessels lacking the protective blood-brain barrier (BBB). Glial cells, by virtue of their plasticity and their ideal location at the interface of blood vessels and neurons, participate in the integration and transmission of peripheral information to neuronal networks in the brain for the neuroendocrine control of whole-body metabolism. Metabolic diseases, such as obesity and type 2 diabetes, can disrupt the brain-to-periphery communication mediated by glial cells, highlighting the relevance of these cell types in the pathophysiology of such complications. An improved understanding of how glial cells integrate and respond to metabolic and humoral signals has become a priority for the discovery of promising therapeutic strategies to treat metabolic disorders. This Review highlights the role of glial cells in the exchange of metabolic signals between the periphery and the brain that are relevant for the regulation of whole-body energy homeostasis.
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Affiliation(s)
- Sreekala Nampoothiri
- Univ. Lille, Inserm, CHU Lille, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Lille Neuroscience & Cognition, UMR-S1172, EGID, DISTALZ, Lille, France
| | - Ruben Nogueiras
- Universidade de Santiago de Compostela-Instituto de Investigation Sanitaria, Santiago de Compostela, Spain
- CIBER Fisiopatologia de la Obesidad y Nutrition, Santiago de Compostela, Spain
| | - Markus Schwaninger
- Institute for Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Lübeck, Germany
| | - Vincent Prevot
- Univ. Lille, Inserm, CHU Lille, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Lille Neuroscience & Cognition, UMR-S1172, EGID, DISTALZ, Lille, France.
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10
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Melatonin in ventricular and subarachnoid cerebrospinal fluid: Its function in the neural glymphatic network and biological significance for neurocognitive health. Biochem Biophys Res Commun 2022; 605:70-81. [DOI: 10.1016/j.bbrc.2022.03.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 03/02/2022] [Accepted: 03/04/2022] [Indexed: 12/13/2022]
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11
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Dardente H, Simonneaux V. GnRH and the photoperiodic control of seasonal reproduction: Delegating the task to kisspeptin and RFRP-3. J Neuroendocrinol 2022; 34:e13124. [PMID: 35384117 DOI: 10.1111/jne.13124] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 02/22/2022] [Accepted: 03/03/2022] [Indexed: 10/18/2022]
Abstract
Synchronization of mammalian breeding activity to the annual change of photoperiod and environmental conditions is of the utmost importance for individual survival and species perpetuation. Subsequent to the early 1960s, when the central role of melatonin in this adaptive process was demonstrated, our comprehension of the mechanisms through which light regulates gonadal activity has increased considerably. The current model for the photoperiodic neuroendocrine system points to pivotal roles for the melatonin-sensitive pars tuberalis (PT) and its seasonally-regulated production of thyroid-stimulating hormone (TSH), as well as for TSH-sensitive hypothalamic tanycytes, radial glia-like cells located in the basal part of the third ventricle. Tanycytes respond to TSH through increased expression of thyroid hormone (TH) deiodinase 2 (Dio2), which leads to heightened production of intrahypothalamic triiodothyronine (T3) during longer days of spring and summer. There is strong evidence that this local, long-day driven, increase in T3 links melatonin input at the PT to gonadotropin-releasing hormone (GnRH) output, to align breeding with the seasons. The mechanism(s) through which T3 impinges upon GnRH remain(s) unclear. However, two distinct neuronal populations of the medio-basal hypothalamus, which express the (Arg)(Phe)-amide peptides kisspeptin and RFamide-related peptide-3, appear to be well-positioned to relay this seasonal T3 message towards GnRH neurons. Here, we summarize our current understanding of the cellular, molecular and neuroendocrine players, which keep track of photoperiod and ultimately govern GnRH output and seasonal breeding.
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Affiliation(s)
- Hugues Dardente
- CNRS, IFCE, INRAE, Université de Tours, PRC, Nouzilly, France
| | - Valérie Simonneaux
- Institute for Cellular and Integrative Neuroscience, University of Strasbourg, Strasbourg, France
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12
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Sicardi A, Prévot V. [MCH neurons regulate fenestration of the median eminence vascular loops reaching the arcuate nucleus of the hypothalamus]. Med Sci (Paris) 2022; 38:248-251. [PMID: 35333160 DOI: 10.1051/medsci/2022016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Alicia Sicardi
- Univ. Lille, Inserm, CHU Lille, Laboratoire de Développement et plasticité du cerveau neuroendocrine, Lille Neuroscience et Cognition, UMR-S1172, 1 place de Verdun, 59045 Lille Cedex, France
| | - Vincent Prévot
- Univ. Lille, Inserm, CHU Lille, Laboratoire de Développement et plasticité du cerveau neuroendocrine, Lille Neuroscience et Cognition, UMR-S1172, 1 place de Verdun, 59045 Lille Cedex, France
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13
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Imbernon M, Dehouck B, Prevot V. Glycemic control: Tanycytes march to the beat of the suprachiasmatic drummer. Curr Biol 2022; 32:R173-R176. [DOI: 10.1016/j.cub.2022.01.038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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