1
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Cleland NRW, Bruce KD. Fatty acid sensing in the brain: The role of glial-neuronal metabolic crosstalk and horizontal lipid flux. Biochimie 2024; 223:166-178. [PMID: 35998849 DOI: 10.1016/j.biochi.2022.08.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 07/01/2022] [Accepted: 08/17/2022] [Indexed: 11/15/2022]
Abstract
The central control of energy homeostasis is a regulatory axis that involves the sensing of nutrients, signaling molecules, adipokines, and neuropeptides by neurons in the metabolic centers of the hypothalamus. However, non-neuronal glial cells are also abundant in the hypothalamus and recent findings have underscored the importance of the metabolic crosstalk and horizontal lipid flux between glia and neurons to the downstream regulation of systemic metabolism. New transgenic models and high-resolution analyses of glial phenotype and function have revealed that glia sit at the nexus between lipid metabolism and neural function, and may markedly impact the brain's response to dietary lipids or the supply of brain-derived lipids. Glia comprise the main cellular compartment involved in lipid synthesis, lipoprotein production, and lipid processing in the brain. In brief, tanycytes provide an interface between peripheral lipids and neurons, astrocytes produce lipoproteins that transport lipids to neurons and other glia, oligodendrocytes use brain-derived and dietary lipids to myelinate axons and influence neuronal function, while microglia can remove unwanted lipids in the brain and contribute to lipid re-utilization through cholesterol efflux. Here, we review recent findings regarding glial-lipid transport and highlight the specific molecular factors necessary for lipid processing in the brain, and how dysregulation of glial-neuronal metabolic crosstalk contributes to imbalanced energy homeostasis. Furthering our understanding of glial lipid metabolism will guide the design of future studies that target horizontal lipid processing in the brain to ameliorate the risk of developing obesity and metabolic disease.
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Affiliation(s)
- Nicholas R W Cleland
- Division of Endocrinology Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Kimberley D Bruce
- Division of Endocrinology Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA.
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2
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Leenders F, Koole L, Slaets H, Tiane A, Hove DVD, Vanmierlo T. Navigating oligodendrocyte precursor cell aging in brain health. Mech Ageing Dev 2024; 220:111959. [PMID: 38950628 DOI: 10.1016/j.mad.2024.111959] [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: 05/02/2024] [Revised: 06/17/2024] [Accepted: 06/24/2024] [Indexed: 07/03/2024]
Abstract
Oligodendrocyte precursor cells (OPCs) comprise 5-8 % of the adult glial cell population and stand out as the most proliferative cell type in the central nervous system (CNS). OPCs are responsible for generating oligodendrocytes (OLs), the myelinating cells of the CNS. However, OPC functions decline as we age, resulting in impaired differentiation and inadequate remyelination. This review explores the cellular and molecular changes associated with OPC aging, and their impact on OPC differentiation and functionality. Furthermore, it examines the impact of OPC aging within the context of multiple sclerosis and Alzheimer's disease, both neurodegenerative conditions wherein aged OPCs exacerbate disease progression by impeding remyelination. Moreover, various pharmacological interventions targeting pathways related to senescence and differentiation are discussed as potential strategies to rejuvenate aged OPCs. Enhancing our understanding of OPC aging mechanisms holds promise for developing new therapies to improve remyelination and repair in age-related neurodegenerative disorders.
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Affiliation(s)
- Freddy Leenders
- Department Psychiatry and Neuropsychology, Division Translational Neuroscience, Mental Health and Neuroscience Research Institute, Maastricht University, Maastricht, the Netherlands; Department of Neuroscience, Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium
| | - Lisa Koole
- Department Psychiatry and Neuropsychology, Division Translational Neuroscience, Mental Health and Neuroscience Research Institute, Maastricht University, Maastricht, the Netherlands; Department of Neuroscience, Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium
| | - Helena Slaets
- University MS Centre (UMSC) Hasselt, Pelt, Belgium; Neuro-Immune Connections and Repair Lab, Department of Immunology and Infection, Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
| | - Assia Tiane
- Department Psychiatry and Neuropsychology, Division Translational Neuroscience, Mental Health and Neuroscience Research Institute, Maastricht University, Maastricht, the Netherlands; Department of Neuroscience, Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium; University MS Centre (UMSC) Hasselt, Pelt, Belgium
| | - Daniel van den Hove
- Department Psychiatry and Neuropsychology, Division Translational Neuroscience, Mental Health and Neuroscience Research Institute, Maastricht University, Maastricht, the Netherlands
| | - Tim Vanmierlo
- Department Psychiatry and Neuropsychology, Division Translational Neuroscience, Mental Health and Neuroscience Research Institute, Maastricht University, Maastricht, the Netherlands; Department of Neuroscience, Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium; University MS Centre (UMSC) Hasselt, Pelt, Belgium.
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3
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McKay EJ, Luijten I, Weng X, Martinez de Morentin PB, De Frutos González E, Gao Z, Kolonin MG, Heisler LK, Semple RK. Mesenchymal-specific Alms1 knockout in mice recapitulates metabolic features of Alström syndrome. Mol Metab 2024; 84:101933. [PMID: 38583571 PMCID: PMC11047791 DOI: 10.1016/j.molmet.2024.101933] [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: 02/05/2024] [Accepted: 04/01/2024] [Indexed: 04/09/2024] Open
Abstract
OBJECTIVE Alström Syndrome (AS), caused by biallelic ALMS1 mutations, includes obesity with disproportionately severe insulin resistant diabetes, dyslipidemia, and fatty liver. Prior studies suggest that hyperphagia is accounted for by loss of ALMS1 function in hypothalamic neurones, whereas disproportionate metabolic complications may be due to impaired adipose tissue expandability. We tested this by comparing the metabolic effects of global and mesenchymal stem cell (MSC)-specific Alms1 knockout. METHODS Global Alms1 knockout (KO) mice were generated by crossing floxed Alms1 and CAG-Cre mice. A Pdgfrα-Cre driver was used to abrogate Alms1 function selectively in MSCs and their descendants, including preadipocytes. We combined metabolic phenotyping of global and Pdgfrα+ Alms1-KO mice on a 45% fat diet with measurements of body composition and food intake, and histological analysis of metabolic tissues. RESULTS Assessed on 45% fat diet to promote adipose expansion, global Alms1 KO caused hyperphagia, obesity, insulin resistance, dyslipidaemia, and fatty liver. Pdgfrα-cre driven KO of Alms1 (MSC KO) recapitulated insulin resistance, fatty liver, and dyslipidaemia in both sexes. Other phenotypes were sexually dimorphic: increased fat mass was only present in female Alms1 MSC KO mice. Hyperphagia was not evident in male Alms1 MSC KO mice, but was found in MSC KO females, despite no neuronal Pdgfrα expression. CONCLUSIONS Mesenchymal deletion of Alms1 recapitulates metabolic features of AS, including fatty liver. This confirms a key role for Alms1 in the adipose lineage, where its loss is sufficient to cause systemic metabolic effects and damage to remote organs. Hyperphagia in females may depend on Alms1 deficiency in oligodendrocyte precursor cells rather than neurones. AS should be regarded as a forme fruste of lipodystrophy.
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Affiliation(s)
- Eleanor J McKay
- Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - Ineke Luijten
- Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - Xiong Weng
- Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - Pablo B Martinez de Morentin
- The Rowett Institute, University of Aberdeen, Aberdeen, UK; School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Elvira De Frutos González
- The Rowett Institute, University of Aberdeen, Aberdeen, UK; Área de Fisiología Humana, Departamento de Ciencias básicas de la Salud, Facultad de ciencias de la Salud, Universidad Rey Juan Carlos, 28922 Alcorcón, Madrid, Spain
| | - Zhanguo Gao
- Institute of Molecular Medicine, University of Texas Health Sciences Center at Houston, Houston, TX 77030, USA
| | - Mikhail G Kolonin
- Institute of Molecular Medicine, University of Texas Health Sciences Center at Houston, Houston, TX 77030, USA
| | - Lora K Heisler
- The Rowett Institute, University of Aberdeen, Aberdeen, UK
| | - Robert K Semple
- Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK; MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK.
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4
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Srivastava T, Nguyen H, Haden G, Diba P, Sowa S, LaNguyen N, Reed-Dustin W, Zhu W, Gong X, Harris EN, Baltan S, Back SA. TSG-6-Mediated Extracellular Matrix Modifications Regulate Hypoxic-Ischemic Brain Injury. J Neurosci 2024; 44:e2215232024. [PMID: 38569926 PMCID: PMC11112645 DOI: 10.1523/jneurosci.2215-23.2024] [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: 11/28/2023] [Revised: 03/24/2024] [Accepted: 03/27/2024] [Indexed: 04/05/2024] Open
Abstract
Proteoglycans containing link domains modify the extracellular matrix (ECM) to regulate cellular homeostasis and can also sensitize tissues/organs to injury and stress. Hypoxic-ischemic (H-I) injury disrupts cellular homeostasis by activating inflammation and attenuating regeneration and repair pathways. In the brain, the main component of the ECM is the glycosaminoglycan hyaluronic acid (HA), but whether HA modifications of the ECM regulate cellular homeostasis and response to H-I injury is not known. In this report, employing both male and female mice, we demonstrate that link-domain-containing proteoglycan, TNFα-stimulated gene-6 (TSG-6), is active in the brain from birth onward and differentially modifies ECM HA during discrete neurodevelopmental windows. ECM HA modification by TSG-6 enables it to serve as a developmental switch to regulate the activity of the Hippo pathway effector protein, yes-associated protein 1 (YAP1), in the maturing brain and in response to H-I injury. Mice that lack TSG-6 expression display dysregulated expression of YAP1 targets, excitatory amino acid transporter 1 (EAAT1; glutamate-aspartate transporter) and 2 (EAAT2; glutamate transporter-1). Dysregulation of YAP1 activation in TSG-6-/- mice coincides with age- and sex-dependent sensitization of the brain to H-I injury such that 1-week-old neonates display an anti-inflammatory response in contrast to an enhanced proinflammatory injury reaction in 3-month-old adult males but not females. Our findings thus support that a key regulator of age- and sex-dependent H-I injury response in the mouse brain is modulation of the Hippo-YAP1 pathway by TSG-6-dependent ECM modifications.
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Affiliation(s)
- Taasin Srivastava
- Department of Pediatrics, Oregon Health and Science University (OHSU), Portland, Oregon 97239
| | - Hung Nguyen
- Division of Anesthesiology and Perioperative Medicine (APOM), Oregon Health and Science University (OHSU), Portland, Oregon 97239
| | - Gage Haden
- Department of Pediatrics, Oregon Health and Science University (OHSU), Portland, Oregon 97239
| | - Parham Diba
- Department of Pediatrics, Oregon Health and Science University (OHSU), Portland, Oregon 97239
| | - Steven Sowa
- Department of Pediatrics, Oregon Health and Science University (OHSU), Portland, Oregon 97239
| | - Norah LaNguyen
- Department of Pediatrics, Oregon Health and Science University (OHSU), Portland, Oregon 97239
| | - William Reed-Dustin
- Department of Pediatrics, Oregon Health and Science University (OHSU), Portland, Oregon 97239
| | - Wenbin Zhu
- Division of Anesthesiology and Perioperative Medicine (APOM), Oregon Health and Science University (OHSU), Portland, Oregon 97239
| | - Xi Gong
- Department of Pediatrics, Oregon Health and Science University (OHSU), Portland, Oregon 97239
| | - Edward N Harris
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588
| | - Selva Baltan
- Division of Anesthesiology and Perioperative Medicine (APOM), Oregon Health and Science University (OHSU), Portland, Oregon 97239
| | - Stephen A Back
- Department of Pediatrics, Oregon Health and Science University (OHSU), Portland, Oregon 97239
- Department of Neurology, Oregon Health and Science University (OHSU), Portland, Oregon 97239
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5
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Santos-Silva T, Colodete DAE, Lisboa JRF, Silva Freitas Í, Lopes CFB, Hadera V, Lima TSA, Souza AJ, Gomes FV. Perineuronal nets as regulators of parvalbumin interneuron function: Factors implicated in their formation and degradation. Basic Clin Pharmacol Toxicol 2024; 134:614-628. [PMID: 38426366 DOI: 10.1111/bcpt.13994] [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: 10/09/2023] [Revised: 01/12/2024] [Accepted: 02/12/2024] [Indexed: 03/02/2024]
Abstract
The brain extracellular matrix (ECM) has garnered increasing attention as a fundamental component of brain function in a predominantly "neuron-centric" paradigm. Particularly, the perineuronal nets (PNNs), a specialized net-like structure formed by ECM aggregates, play significant roles in brain development and physiology. PNNs enwrap synaptic junctions in various brain regions, precisely balancing new synaptic formation and long-term stabilization, and are highly dynamic entities that change in response to environmental stimuli, especially during the neurodevelopmental period. They are found mainly surrounding parvalbumin (PV)-expressing GABAergic interneurons, being proposed to promote PV interneuron maturation and protect them against oxidative stress and neurotoxic agents. This structural and functional proximity underscores the crucial role of PNNs in modulating PV interneuron function, which is critical for the excitatory/inhibitory balance and, consequently, higher-level behaviours. This review delves into the molecular underpinnings governing PNNs formation and degradation, elucidating their functional interactions with PV interneurons. In the broader physiological context and brain-related disorders, we also explore their intricate relationship with other molecules, such as reactive oxygen species and metalloproteinases, as well as glial cells. Additionally, we discuss potential therapeutic strategies for modulating PNNs in brain disorders.
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Affiliation(s)
- Thamyris Santos-Silva
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Debora A E Colodete
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | | | - Ícaro Silva Freitas
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Caio Fábio Baeta Lopes
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Victor Hadera
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Thaís Santos Almeida Lima
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Adriana Jesus Souza
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Felipe V Gomes
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
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6
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Buller S, Blouet C. Brain access of incretins and incretin receptor agonists to their central targets relevant for appetite suppression and weight loss. Am J Physiol Endocrinol Metab 2024; 326:E472-E480. [PMID: 38381398 PMCID: PMC11193531 DOI: 10.1152/ajpendo.00250.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 01/05/2024] [Accepted: 02/13/2024] [Indexed: 02/22/2024]
Abstract
New incretin-based pharmacotherapies provide efficient and safe therapeutic options to curb appetite and produce weight loss in patients with obesity. Delivered systemically, these molecules produce pleiotropic metabolic benefits, but the target sites mediating their weight-suppressive action are located within the brain. Recent research has increased our understanding of the neural circuits and behavioral mechanisms involved in the anorectic and metabolic consequences of glucagon-like peptide 1 (GLP-1)-based weight loss strategies, yet little is known about how these drugs access their functional targets in the brain to produce sustained weight loss. The majority of brain cells expressing incretin receptors are located behind the blood-brain barrier, shielded from the circulation and fluctuations in the availability of peripheral signals, which is a major challenge for the development of CNS-targeted therapeutic peptides. GLP-1 receptor (GLP-1R) agonists with increased half-life and enhanced therapeutic benefit do not cross the blood-brain barrier, yet they manage to access discrete brain sites relevant to the regulation of energy homeostasis. In this review, we give a brief overview of the different routes for peptide hormones to access the brain. We then examine the evidence informing the routes employed by incretins and incretin receptor agonists to access brain targets relevant for their appetite and weight-suppressive actions. We highlight existing controversies and suggest future directions to further establish the functionally relevant access routes for GLP-1-based weight loss compounds, which might guide the development and selection of the future generation of incretin receptor polypharmacologies.
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Affiliation(s)
- Sophie Buller
- Medical Research Council (MRC) Metabolic Diseases Unit, Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
| | - Clemence Blouet
- Medical Research Council (MRC) Metabolic Diseases Unit, Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
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7
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Huang Y, Wang A, Zhou W, Li B, Zhang L, Rudolf AM, Jin Z, Hambly C, Wang G, Speakman JR. Maternal dietary fat during lactation shapes single nucleus transcriptomic profile of postnatal offspring hypothalamus in a sexually dimorphic manner in mice. Nat Commun 2024; 15:2382. [PMID: 38493217 PMCID: PMC10944494 DOI: 10.1038/s41467-024-46589-x] [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: 09/28/2023] [Accepted: 03/01/2024] [Indexed: 03/18/2024] Open
Abstract
Maternal overnutrition during lactation predisposes offspring to develop metabolic diseases and exacerbates the relevant syndromes in males more than females in later life. The hypothalamus is a heterogenous brain region that regulates energy balance. Here we combined metabolic trait quantification of mother and offspring mice under low and high fat diet (HFD) feeding during lactation, with single nucleus transcriptomic profiling of their offspring hypothalamus at peak lacation to understand the cellular and molecular alterations in response to maternal dietary pertubation. We found significant expansion in neuronal subpopulations including histaminergic (Hdc), arginine vasopressin/retinoic acid receptor-related orphan receptor β (Avp/Rorb) and agouti-related peptide/neuropeptide Y (AgRP/Npy) in male offspring when their mothers were fed HFD, and increased Npy-astrocyte interactions in offspring responding to maternal overnutrition. Our study provides a comprehensive offspring hypothalamus map at the peak lactation and reveals how the cellular subpopulations respond to maternal dietary fat in a sex-specific manner during development.
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Affiliation(s)
- Yi Huang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- Broad Institute of MIT and Harvard, Metabolism Program, Cambridge, MA, 02142, USA
| | - Anyongqi Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Wenjiang Zhou
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Centre for Evolutionary Biology, Fudan University, Shanghai, 200438, China
| | - Baoguo Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- Tianjian Laboratory of Advanced Biomedical Sciences, Zhengzhou University, Zhengzhou, 450001, China
| | - Linshan Zhang
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Centre for Evolutionary Biology, Fudan University, Shanghai, 200438, China
| | - Agata M Rudolf
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Zengguang Jin
- Shenzhen Key Laboratory of Metabolic Health, Center for Energy Metabolism and Reproduction, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Catherine Hambly
- School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 3FX, UK
| | - Guanlin Wang
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Centre for Evolutionary Biology, Fudan University, Shanghai, 200438, China.
| | - John R Speakman
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.
- Shenzhen Key Laboratory of Metabolic Health, Center for Energy Metabolism and Reproduction, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China.
- School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 3FX, UK.
- China Medical University, Shenyang, Liaoning, 110122, China.
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8
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Sun J, Wang X, Sun R, Xiao X, Wang Y, Peng Y, Gao Y. Microglia shape AgRP neuron postnatal development via regulating perineuronal net plasticity. Mol Psychiatry 2024; 29:306-316. [PMID: 38001338 DOI: 10.1038/s41380-023-02326-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 10/31/2023] [Accepted: 11/13/2023] [Indexed: 11/26/2023]
Abstract
The hypothalamus plays a crucial role in controlling metabolism and energy balance, with Agouti-related protein (AgRP) neurons and proopiomelanocortin (POMC) neurons being essential components of this process. The proper development of these neurons is important for metabolic regulation in later life. Microglia, the resident immune cells in the brain, have been shown to significantly influence neurodevelopment. However, their role in shaping the postnatal development of hypothalamic neural circuits remains underexplored. In this study, we investigated the dynamic changes of microglia in the hypothalamic arcuate nucleus (ARC) during lactation and their impact on the maturation of AgRP and POMC neurons. We demonstrated that microglial depletion during a critical period of ARC neuron maturation increases the number of AgRP neurons and fiber density, with less effect on POMC neurons. This depletion also resulted in increased neonatal feeding behavior. Mechanistically, microglia can engulf perineuronal net (PNN) components surrounding AgRP neurons both in vivo and ex vivo. The absence of microglia leads to increased PNN formation and enhanced leptin sensitivity in ARC. Our findings suggest that microglia participate in the postnatal development of AgRP neurons by regulating the plasticity of PNN formation. This study contributes to a better understanding of microglia's role in shaping hypothalamic neural circuits during postnatal development and their impact on metabolism regulation.
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Affiliation(s)
- Jia Sun
- Key Laboratory of Cardiovascular and Cerebrovascular Medicine, School of Pharmacy, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, P. R. China
| | - Xinyuan Wang
- Key Laboratory of Cardiovascular and Cerebrovascular Medicine, School of Pharmacy, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, P. R. China
- Geriatric Hospital of Nanjing Medical University, Nanjing, 210009, P. R. China
| | - Rui Sun
- Key Laboratory of Cardiovascular and Cerebrovascular Medicine, School of Pharmacy, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, P. R. China
| | - Xiaoao Xiao
- Key Laboratory of Cardiovascular and Cerebrovascular Medicine, School of Pharmacy, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, P. R. China
| | - Yu Wang
- Key Laboratory of Cardiovascular and Cerebrovascular Medicine, School of Pharmacy, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, P. R. China
| | - Yu Peng
- Key Laboratory of Cardiovascular and Cerebrovascular Medicine, School of Pharmacy, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, P. R. China
| | - Yuanqing Gao
- Key Laboratory of Cardiovascular and Cerebrovascular Medicine, School of Pharmacy, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, P. R. China.
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9
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Elbaz B, Darwish A, Vardy M, Isaac S, Tokars HM, Dzhashiashvili Y, Korshunov K, Prakriya M, Eden A, Popko B. The bone transcription factor Osterix controls extracellular matrix- and node of Ranvier-related gene expression in oligodendrocytes. Neuron 2024; 112:247-263.e6. [PMID: 37924811 PMCID: PMC10843489 DOI: 10.1016/j.neuron.2023.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 08/24/2023] [Accepted: 10/04/2023] [Indexed: 11/06/2023]
Abstract
Oligodendrocytes are the primary producers of many extracellular matrix (ECM)-related proteins found in the CNS. Therefore, oligodendrocytes play a critical role in the determination of brain stiffness, node of Ranvier formation, perinodal ECM deposition, and perineuronal net formation, all of which depend on the ECM. Nevertheless, the transcription factors that control ECM-related gene expression in oligodendrocytes remain unknown. Here, we found that the transcription factor Osterix (also known as Sp7) binds in proximity to genes important for CNS ECM and node of Ranvier formation and mediates their expression. Oligodendrocyte-specific ablation of Sp7 changes ECM composition and brain stiffness and results in aberrant node of Ranvier formation. Sp7 is known to control osteoblast maturation and bone formation. Our comparative analyses suggest that Sp7 plays a conserved biological role in oligodendrocytes and in bone-forming cells, where it mediates brain and bone tissue stiffness by controlling expression of ECM components.
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Affiliation(s)
- Benayahu Elbaz
- Department of Neurology, Division of Multiple Sclerosis and Neuroimmunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
| | - Alaa Darwish
- Department of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Maia Vardy
- Department of Neurology, Division of Multiple Sclerosis and Neuroimmunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Sara Isaac
- Department of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Haley Margaret Tokars
- Department of Neurology, Division of Multiple Sclerosis and Neuroimmunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Yulia Dzhashiashvili
- Department of Neurology, Division of Multiple Sclerosis and Neuroimmunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Kirill Korshunov
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Murali Prakriya
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Amir Eden
- Department of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Brian Popko
- Department of Neurology, Division of Multiple Sclerosis and Neuroimmunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
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10
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Chen B, de Launoit E, Renier N, Schneeberger M. Central myelin dysfunction bridges obesity and neurological diseases. Trends Endocrinol Metab 2024; 35:7-10. [PMID: 37798242 PMCID: PMC10840937 DOI: 10.1016/j.tem.2023.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 09/11/2023] [Accepted: 09/12/2023] [Indexed: 10/07/2023]
Abstract
The central nervous system (CNS) relies on myelin for proper functioning. Myelin remodeling is a risk factor for neurometabolic and endocrine malfunction, resulting in cognitive decline and heightened susceptibility to neurological diseases. The plasticity of myelin upon nutrient shifts may lead to dietary and hormonal interventions for preventing and treating neural complications.
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Affiliation(s)
- Bandy Chen
- Laboratory of Neurovascular Control of Homeostasis, Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT, USA.
| | - Elisa de Launoit
- Laboratoire de Plasticité Structurale Sorbonne Université, ICM Paris Brain Institute, INSERM U1127, CNRS UMR7225, 75013 Paris, France
| | - Nicolas Renier
- Laboratoire de Plasticité Structurale Sorbonne Université, ICM Paris Brain Institute, INSERM U1127, CNRS UMR7225, 75013 Paris, France.
| | - Marc Schneeberger
- Laboratory of Neurovascular Control of Homeostasis, Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT, USA; Wu Tsai Institute for Mind and Brain, Yale University, New Haven, CT, USA.
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11
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Chambers ME, Nuibe EH, Reno-Bernstein CM. Brain Regulation of Cardiac Function during Hypoglycemia. Metabolites 2023; 13:1089. [PMID: 37887414 PMCID: PMC10608630 DOI: 10.3390/metabo13101089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/02/2023] [Accepted: 10/16/2023] [Indexed: 10/28/2023] Open
Abstract
Hypoglycemia occurs frequently in people with type 1 and type 2 diabetes. Hypoglycemia activates the counter-regulatory response. Besides peripheral glucose sensors located in the pancreas, mouth, gastrointestinal tract, portal vein, and carotid body, many brain regions also contain glucose-sensing neurons that detect this fall in glucose. The autonomic nervous system innervates the heart, and during hypoglycemia, can cause many changes. Clinical and animal studies have revealed changes in electrocardiograms during hypoglycemia. Cardiac repolarization defects (QTc prolongation) occur during moderate levels of hypoglycemia. When hypoglycemia is severe, it can be fatal. Cardiac arrhythmias are thought to be the major mediator of sudden death due to severe hypoglycemia. Both the sympathetic and parasympathetic nervous systems of the brain have been implicated in regulating these arrhythmias. Besides cardiac arrhythmias, hypoglycemia can have profound changes in the heart and most of these changes are exacerbated in the setting of diabetes. A better understanding of how the brain regulates cardiac changes during hypoglycemia will allow for better therapeutic intervention to prevent cardiovascular death associated with hypoglycemia in people with diabetes. The aim of this paper is to provide a narrative review of what is known in the field regarding how the brain regulates the heart during hypoglycemia.
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Affiliation(s)
| | | | - Candace M. Reno-Bernstein
- Division of Endocrinology, Metabolism, and Diabetes, University of Utah School of Medicine, Salt Lake City, UT 84112, USA (E.H.N.)
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12
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McKay EJ, Luijten I, Weng X, Martinez de Morentin PB, De Frutos González E, Gao Z, Kolonin MG, Heisler LK, Semple RK. Mesenchymal-specific Alms1 knockout in mice recapitulates key metabolic features of Alström Syndrome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.12.562074. [PMID: 37873427 PMCID: PMC10592792 DOI: 10.1101/2023.10.12.562074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Background Alström Syndrome (AS), a multi-system disease caused by mutations in the ALMS1 gene, includes obesity with disproportionately severe insulin resistant diabetes, dyslipidemia, and hepatosteatosis. How loss of ALMS1 causes this phenotype is poorly understood, but prior studies have circumstancially implicated impaired adipose tissue expandability. We set out to test this by comparing the metabolic effects of selective Alms1 knockout in mesenchymal cells including preadipocytes to those of global Alms1 knockout. Methods Global Alms1 knockout (KO) mice were generated by crossing floxed Alms1 and CAG-Cre mice. A Pdgfrα -Cre driver was used to abrogate Alms1 function selectively in mesenchymal stem cells (MSCs) and their descendants, including preadipocytes. We combined metabolic phenotyping of global and Pdgfrα + Alms1 -KO mice on a 45% fat diet with measurements of body composition and food intake, and histological analysis of metabolic tissues. Results Global Alms1 KO caused hyperphagia, obesity, insulin resistance, dyslipidaemia, and fatty liver. Pdgfrα - cre driven KO of Alms1 (MSC KO) recapitulated insulin resistance, fatty liver, and dyslipidaemia in both sexes. Other phenotypes were sexually dimorphic: increased fat mass was only present in female Alms1 MSC KO mice. Hyperphagia was not evident in male Alms1 MSC KO mice, but was found in MSC KO females, despite no neuronal Pdgfr α expression. Conclusions Mesenchymal deletion of Alms1 recapitulates the metabolic features of AS, including severe fatty liver. This confirms a key role for Alms1 in the adipose lineage, where its loss is sufficient to cause systemic metabolic effects and damage to remote organs. AS should be regarded as a forme fruste of lipodystrophy. Therapies should prioritise targeting positive energy balance.
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13
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Brüning JC, Fenselau H. Integrative neurocircuits that control metabolism and food intake. Science 2023; 381:eabl7398. [PMID: 37769095 DOI: 10.1126/science.abl7398] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 08/31/2023] [Indexed: 09/30/2023]
Abstract
Systemic metabolism has to be constantly adjusted to the variance of food intake and even be prepared for anticipated changes in nutrient availability. Therefore, the brain integrates multiple homeostatic signals with numerous cues that predict future deviations in energy supply. Recently, our understanding of the neural pathways underlying these regulatory principles-as well as their convergence in the hypothalamus as the key coordinator of food intake, energy expenditure, and glucose metabolism-have been revealed. These advances have changed our view of brain-dependent control of metabolic physiology. In this Review, we discuss new concepts about how alterations in these pathways contribute to the development of prevalent metabolic diseases such as obesity and type 2 diabetes mellitus and how this emerging knowledge may provide new targets for their treatment.
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Affiliation(s)
- Jens C Brüning
- Department of Neuronal Control of Metabolism, Max Planck Institute for Metabolism Research, 50931 Cologne, Germany
- Policlinic for Endocrinology, Diabetes, and Preventive Medicine (PEDP), University Hospital Cologne, 50924 Cologne, Germany
- Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
- National Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Henning Fenselau
- Policlinic for Endocrinology, Diabetes, and Preventive Medicine (PEDP), University Hospital Cologne, 50924 Cologne, Germany
- Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
- Research Group Synaptic Transmission in Energy Homeostasis, Max Planck Institute for Metabolism Research, 50931 Cologne, Germany
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14
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Valeri J, Gisabella B, Pantazopoulos H. Dynamic regulation of the extracellular matrix in reward memory processes: a question of time. Front Cell Neurosci 2023; 17:1208974. [PMID: 37396928 PMCID: PMC10311570 DOI: 10.3389/fncel.2023.1208974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 05/30/2023] [Indexed: 07/04/2023] Open
Abstract
Substance use disorders are a global health problem with increasing prevalence resulting in significant socioeconomic burden and increased mortality. Converging lines of evidence point to a critical role of brain extracellular matrix (ECM) molecules in the pathophysiology of substance use disorders. An increasing number of preclinical studies highlight the ECM as a promising target for development of novel cessation pharmacotherapies. The brain ECM is dynamically regulated during learning and memory processes, thus the time course of ECM alterations in substance use disorders is a critical factor that may impact interpretation of the current studies and development of pharmacological therapies. This review highlights the evidence for the involvement of ECM molecules in reward learning, including drug reward and natural reward such as food, as well as evidence regarding the pathophysiological state of the brain's ECM in substance use disorders and metabolic disorders. We focus on the information regarding time-course and substance specific changes in ECM molecules and how this information can be leveraged for the development of therapeutic strategies.
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Affiliation(s)
- Jake Valeri
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, United States
- Graduate Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS, United States
| | - Barbara Gisabella
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, United States
- Graduate Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS, United States
| | - Harry Pantazopoulos
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, United States
- Graduate Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS, United States
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15
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Abdel-Malek M, Yang L, Miras AD. Pharmacotherapy for chronic obesity management: a look into the future. Intern Emerg Med 2023; 18:1019-1030. [PMID: 37249754 PMCID: PMC10326094 DOI: 10.1007/s11739-023-03237-4] [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: 08/17/2022] [Accepted: 02/17/2023] [Indexed: 05/31/2023]
Abstract
Substantial leaps have been made in the drug discovery front in tackling the growing pandemic of obesity and its metabolic co-morbidities. Greater mechanistic insight and understanding of the gut-brain molecular pathways at play have enabled the pursuit of novel therapeutic agents that possess increasingly efficacious weight-lowering potential whilst remaining safe and tolerable for clinical use. In the wake of glucagon-like peptide 1 (GLP-1) based therapy, we look at recent advances in gut hormone biology that have fermented the development of next generation pharmacotherapy in diabesity that harness synergistic potential. In this paper, we review the latest data from the SURPASS and SURMOUNT clinical trials for the novel 'twincretin', known as Tirzepatide, which has demonstrated sizeable body weight reduction as well as glycaemic efficacy. We also provide an overview of amylin-based combination strategies and other emerging therapies in the pipeline that are similarly providing great promise for the future of chronic management of obesity.
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Affiliation(s)
| | - Lisa Yang
- Imperial College Healthcare NHS Trust, London, UK
| | - Alexander Dimitri Miras
- School of Medicine, Ulster University, Derry~Londonderry, UK
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
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16
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Buller S, Kohnke S, Hansford R, Shimizu T, Richardson WD, Blouet C. Median eminence myelin continuously turns over in adult mice. Mol Metab 2023; 69:101690. [PMID: 36739968 PMCID: PMC9950957 DOI: 10.1016/j.molmet.2023.101690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 01/16/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVE Oligodendrocyte progenitor cell differentiation is regulated by nutritional signals in the adult median eminence (ME), but the consequences on local myelination are unknown. The aim of this study was to characterize myelin plasticity in the ME of adult mice in health or in response to chronic nutritional challenge and determine its relevance to the regulation of energy balance. METHODS We assessed new oligodendrocyte (OL) and myelin generation and stability in the ME of healthy adult male mice using bromodeoxyuridine labelling and genetic fate mapping tools. We evaluated the contribution of microglia to ME myelin plasticity in PLX5622-treated C57BL/6J mice and in Pdgfra-Cre/ERT2;R26R-eYFP;Myrffl/fl mice, where adult oligodendrogenesis is blunted. Next, we investigated how high-fat feeding or caloric restriction impact ME OL lineage progression and myelination. Finally, we characterized the functional relevance of adult oligodendrogenesis on energy balance regulation. RESULTS We show that myelinating OLs are continuously and rapidly generated in the adult ME. Paradoxically, OL number and myelin amounts remain remarkably stable in the adult ME. In fact, the high rate of new OL and myelin generation in the ME is offset by continuous turnover of both. We show that microglia are required for continuous OL and myelin production, and that ME myelin plasticity regulates the recruitment of local immune cells. Finally, we provide evidence that ME myelination is regulated by the body's energetic status and demonstrate that ME OL and myelin plasticity are required for the regulation of energy balance and hypothalamic leptin sensitivity. CONCLUSIONS This study identifies a new mechanism modulating leptin sensitivity and the central control of energy balance and uncovers a previously unappreciated form of structural plasticity in the ME.
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Affiliation(s)
- Sophie Buller
- Wellcome-MRC Institute of Metabolic Science and Medical Research Council Metabolic Disease Unit, University of Cambridge, Cambridge, UK.
| | - Sara Kohnke
- Wellcome-MRC Institute of Metabolic Science and Medical Research Council Metabolic Disease Unit, University of Cambridge, Cambridge, UK.
| | - Robert Hansford
- Wellcome-MRC Institute of Metabolic Science and Medical Research Council Metabolic Disease Unit, University of Cambridge, Cambridge, UK.
| | - Takahiro Shimizu
- Wolfson Institute for Biomedical Research, University College London, London, UK.
| | - William D Richardson
- Wolfson Institute for Biomedical Research, University College London, London, UK.
| | - Clemence Blouet
- Wellcome-MRC Institute of Metabolic Science and Medical Research Council Metabolic Disease Unit, University of Cambridge, Cambridge, UK.
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17
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Cashion JM, Young KM, Sutherland BA. How does neurovascular unit dysfunction contribute to multiple sclerosis? Neurobiol Dis 2023; 178:106028. [PMID: 36736923 DOI: 10.1016/j.nbd.2023.106028] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 01/17/2023] [Accepted: 01/30/2023] [Indexed: 02/04/2023] Open
Abstract
Multiple sclerosis is an inflammatory demyelinating disease of the central nervous system (CNS) and the most common non-traumatic cause of neurological disability in young adults. Multiple sclerosis clinical care has improved considerably due to the development of disease-modifying therapies that effectively modulate the peripheral immune response and reduce relapse frequency. However, current treatments do not prevent neurodegeneration and disease progression, and efforts to prevent multiple sclerosis will be hampered so long as the cause of this disease remains unknown. Risk factors for multiple sclerosis development or severity include vitamin D deficiency, cigarette smoking and youth obesity, which also impact vascular health. People with multiple sclerosis frequently experience blood-brain barrier breakdown, microbleeds, reduced cerebral blood flow and diminished neurovascular reactivity, and it is possible that these vascular pathologies are tied to multiple sclerosis development. The neurovascular unit is a cellular network that controls neuroinflammation, maintains blood-brain barrier integrity, and tightly regulates cerebral blood flow, matching energy supply to neuronal demand. The neurovascular unit is composed of vessel-associated cells such as endothelial cells, pericytes and astrocytes, however neuronal and other glial cell types also comprise the neurovascular niche. Recent single-cell transcriptomics data, indicate that neurovascular cells, particular cells of the microvasculature, are compromised within multiple sclerosis lesions. Large-scale genetic and small-scale cell biology studies also suggest that neurovascular dysfunction could be a primary pathology contributing to multiple sclerosis development. Herein we revisit multiple sclerosis risk factors and multiple sclerosis pathophysiology and highlight the known and potential roles of neurovascular unit dysfunction in multiple sclerosis development and disease progression. We also evaluate the suitability of the neurovascular unit as a potential target for future disease modifying therapies for multiple sclerosis.
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Affiliation(s)
- Jake M Cashion
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia
| | - Kaylene M Young
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania 7000, Australia
| | - Brad A Sutherland
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia.
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18
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Romanò N, Lafont C, Campos P, Guillou A, Fiordelisio T, Hodson DJ, Mollard P, Schaeffer M. Median eminence blood flow influences food intake by regulating ghrelin access to the metabolic brain. JCI Insight 2023; 8:165763. [PMID: 36574295 PMCID: PMC9977422 DOI: 10.1172/jci.insight.165763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 12/21/2022] [Indexed: 12/28/2022] Open
Abstract
Central integration of peripheral appetite-regulating signals ensures maintenance of energy homeostasis. Thus, plasticity of circulating molecule access to neuronal circuits involved in feeding behavior plays a key role in the adaptive response to metabolic changes. However, the mechanisms involved remain poorly understood despite their relevance for therapeutic development. Here, we investigated the role of median eminence mural cells, including smooth muscle cells and pericytes, in modulating gut hormone effects on orexigenic/anorexigenic circuits. We found that conditional activation of median eminence vascular cells impinged on local blood flow velocity and altered ghrelin-stimulated food intake by delaying ghrelin access to target neurons. Thus, activation of median eminence vascular cells modulates food intake in response to peripheral ghrelin by reducing local blood flow velocity and access to the metabolic brain.
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Affiliation(s)
| | - Chrystel Lafont
- Institute of Functional Genomics and,BioCampus Montpellier, University of Montpellier, CNRS, INSERM, F-34094 Montpellier, France
| | | | | | - Tatiana Fiordelisio
- Institute of Functional Genomics and,Laboratorio de Neuroendocrinología Comparada, Laboratorio Nacional de Soluciones Biomiméticas para Diagnóstico y Terapia LaNSBioDyT, Science Facility, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - David J. Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Patrice Mollard
- Institute of Functional Genomics and,BioCampus Montpellier, University of Montpellier, CNRS, INSERM, F-34094 Montpellier, France
| | - Marie Schaeffer
- Institute of Functional Genomics and,Centre de Biologie Structurale, CNRS UMR 5048, INSERM U1054, University of Montpellier, Montpellier, France
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19
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Schwartz MW, Krinsley JS, Faber CL, Hirsch IB, Brownlee M. Brain Glucose Sensing and the Problem of Relative Hypoglycemia. Diabetes Care 2023; 46:237-244. [PMID: 36701597 PMCID: PMC9887623 DOI: 10.2337/dc22-1445] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Accepted: 11/22/2022] [Indexed: 01/27/2023]
Abstract
"Relative hypoglycemia" is an often-overlooked complication of diabetes characterized by an increase in the glycemic threshold for detecting and responding to hypoglycemia. The clinical relevance of this problem is linked to growing evidence that among patients with critical illness, higher blood glucose in the intensive care unit is associated with higher mortality among patients without diabetes but lower mortality in patients with preexisting diabetes and an elevated prehospitalization HbA1c. Although additional studies are needed, the cardiovascular stress associated with hypoglycemia perception, which can occur at normal or even elevated glucose levels in patients with diabetes, offers a plausible explanation for this difference in outcomes. Little is known, however, regarding how hypoglycemia is normally detected by the brain, much less how relative hypoglycemia develops in patients with diabetes. In this article, we explore the role in hypoglycemia detection played by glucose-responsive sensory neurons supplying peripheral vascular beds and/or circumventricular organs. These observations support a model wherein relative hypoglycemia results from diabetes-associated impairment of this neuronal glucose-sensing process. By raising the glycemic threshold for hypoglycemia perception, this impairment may contribute to the increased mortality risk associated with standard glycemic management of critically ill patients with diabetes.
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Affiliation(s)
- Michael W. Schwartz
- Department of Medicine, University of Washington Medicine Diabetes Institute, Seattle, WA
| | - James S. Krinsley
- Stamford Hospital, Stamford, CT
- Columbia Vagelos College of Physicians and Surgeons, New York, NY
| | - Chelsea L. Faber
- Ivy Brain Tumor Center, Department of Neurosurgery, Barrow Neurological Institute, Phoenix, AZ
| | - Irl B. Hirsch
- Department of Medicine, University of Washington Medicine Diabetes Institute, Seattle, WA
| | - Michael Brownlee
- Einstein Diabetes Research Center, Albert Einstein College of Medicine, Bronx, NY
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20
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Belliveau C, Mechawar N, Tanti A. Reply to: "NG2-glia: rising stars in stress-related mental disorders?". Mol Psychiatry 2023; 28:521-522. [PMID: 36481933 DOI: 10.1038/s41380-022-01889-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/08/2022] [Accepted: 11/15/2022] [Indexed: 12/14/2022]
Affiliation(s)
- Claudia Belliveau
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, McGill University, Montreal, QC, Canada.,Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
| | - Naguib Mechawar
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, McGill University, Montreal, QC, Canada. .,Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada. .,Department of Psychiatry, McGill University, Montréal, QC, Canada.
| | - Arnaud Tanti
- UMR 1253, iBrain, Inserm, Université de Tours, Tours, France.
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21
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Brown TE, Sorg BA. Net gain and loss: influence of natural rewards and drugs of abuse on perineuronal nets. Neuropsychopharmacology 2023; 48:3-20. [PMID: 35568740 PMCID: PMC9700711 DOI: 10.1038/s41386-022-01337-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 04/26/2022] [Accepted: 04/28/2022] [Indexed: 12/26/2022]
Abstract
Overindulgence, excessive consumption, and a pattern of compulsive use of natural rewards, such as certain foods or drugs of abuse, may result in the development of obesity or substance use disorder, respectively. Natural rewards and drugs of abuse can trigger similar changes in the neurobiological substrates that drive food- and drug-seeking behaviors. This review examines the impact natural rewards and drugs of abuse have on perineuronal nets (PNNs). PNNs are specialized extracellular matrix structures that ensheathe certain neurons during development over the critical period to provide synaptic stabilization and a protective microenvironment for the cells they surround. This review also analyzes how natural rewards and drugs of abuse impact the density and maturation of PNNs within reward-associated circuitry of the brain, which may contribute to maladaptive food- and drug-seeking behaviors. Finally, we evaluate the relatively few studies that have degraded PNNs to perturb reward-seeking behaviors. Taken together, this review sheds light on the complex way PNNs are regulated by natural rewards and drugs and highlights a need for future studies to delineate the molecular mechanisms that underlie the modification and maintenance of PNNs following exposure to rewarding stimuli.
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Affiliation(s)
- Travis E Brown
- Integrative Physiology and Neuroscience, Washington State University, Pullman, WA, 99164, USA.
| | - Barbara A Sorg
- R.S. Dow Neurobiology, Legacy Research Institute, Portland, OR, 97232, USA
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22
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Cristobal CD, Lee HK. Development of myelinating glia: An overview. Glia 2022; 70:2237-2259. [PMID: 35785432 PMCID: PMC9561084 DOI: 10.1002/glia.24238] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 06/24/2022] [Accepted: 06/24/2022] [Indexed: 01/07/2023]
Abstract
Myelin is essential to nervous system function, playing roles in saltatory conduction and trophic support. Oligodendrocytes (OLs) and Schwann cells (SCs) form myelin in the central and peripheral nervous systems respectively and follow different developmental paths. OLs are neural stem-cell derived and follow an intrinsic developmental program resulting in a largely irreversible differentiation state. During embryonic development, OL precursor cells (OPCs) are produced in distinct waves originating from different locations in the central nervous system, with a subset developing into myelinating OLs. OPCs remain evenly distributed throughout life, providing a population of responsive, multifunctional cells with the capacity to remyelinate after injury. SCs derive from the neural crest, are highly dependent on extrinsic signals, and have plastic differentiation states. SC precursors (SCPs) are produced in early embryonic nerve structures and differentiate into multipotent immature SCs (iSCs), which initiate radial sorting and differentiate into myelinating and non-myelinating SCs. Differentiated SCs retain the capacity to radically change phenotypes in response to external signals, including becoming repair SCs, which drive peripheral regeneration. While several transcription factors and myelin components are common between OLs and SCs, their differentiation mechanisms are highly distinct, owing to their unique lineages and their respective environments. In addition, both OLs and SCs respond to neuronal activity and regulate nervous system output in reciprocal manners, possibly through different pathways. Here, we outline their basic developmental programs, mechanisms regulating their differentiation, and recent advances in the field.
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Affiliation(s)
- Carlo D. Cristobal
- Integrative Program in Molecular and Biomedical SciencesBaylor College of MedicineHoustonTexasUSA,Jan and Dan Duncan Neurological Research InstituteTexas Children's HospitalHoustonTexasUSA
| | - Hyun Kyoung Lee
- Integrative Program in Molecular and Biomedical SciencesBaylor College of MedicineHoustonTexasUSA,Jan and Dan Duncan Neurological Research InstituteTexas Children's HospitalHoustonTexasUSA,Department of PediatricsBaylor College of MedicineHoustonTexasUSA,Department of NeuroscienceBaylor College of MedicineHoustonTexasUSA
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23
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Steuernagel L, Lam BYH, Klemm P, Dowsett GKC, Bauder CA, Tadross JA, Hitschfeld TS, Del Rio Martin A, Chen W, de Solis AJ, Fenselau H, Davidsen P, Cimino I, Kohnke SN, Rimmington D, Coll AP, Beyer A, Yeo GSH, Brüning JC. HypoMap-a unified single-cell gene expression atlas of the murine hypothalamus. Nat Metab 2022; 4:1402-1419. [PMID: 36266547 PMCID: PMC9584816 DOI: 10.1038/s42255-022-00657-y] [Citation(s) in RCA: 59] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 09/07/2022] [Indexed: 01/20/2023]
Abstract
The hypothalamus plays a key role in coordinating fundamental body functions. Despite recent progress in single-cell technologies, a unified catalog and molecular characterization of the heterogeneous cell types and, specifically, neuronal subtypes in this brain region are still lacking. Here, we present an integrated reference atlas, 'HypoMap,' of the murine hypothalamus, consisting of 384,925 cells, with the ability to incorporate new additional experiments. We validate HypoMap by comparing data collected from Smart-Seq+Fluidigm C1 and bulk RNA sequencing of selected neuronal cell types with different degrees of cellular heterogeneity. Finally, via HypoMap, we identify classes of neurons expressing glucagon-like peptide-1 receptor (Glp1r) and prepronociceptin (Pnoc), and validate them using single-molecule in situ hybridization. Collectively, HypoMap provides a unified framework for the systematic functional annotation of murine hypothalamic cell types, and it can serve as an important platform to unravel the functional organization of hypothalamic neurocircuits and to identify druggable targets for treating metabolic disorders.
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Affiliation(s)
- Lukas Steuernagel
- Department of Neuronal Control of Metabolism, Max Planck Institute for Metabolism Research, Cologne, Germany
| | - Brian Y H Lam
- Medical Research Council Metabolic Diseases Unit, Wellcome-MRC Institute of Metabolic Science - Metabolic Research Laboratories, University of Cambridge, Cambridge, UK
| | - Paul Klemm
- Department of Neuronal Control of Metabolism, Max Planck Institute for Metabolism Research, Cologne, Germany
| | - Georgina K C Dowsett
- Medical Research Council Metabolic Diseases Unit, Wellcome-MRC Institute of Metabolic Science - Metabolic Research Laboratories, University of Cambridge, Cambridge, UK
| | - Corinna A Bauder
- Department of Neuronal Control of Metabolism, Max Planck Institute for Metabolism Research, Cologne, Germany
| | - John A Tadross
- Medical Research Council Metabolic Diseases Unit, Wellcome-MRC Institute of Metabolic Science - Metabolic Research Laboratories, University of Cambridge, Cambridge, UK
- Cambridge Genomics Laboratory, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
- Department of Histopathology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Tamara Sotelo Hitschfeld
- Department of Neuronal Control of Metabolism, Max Planck Institute for Metabolism Research, Cologne, Germany
| | - Almudena Del Rio Martin
- Department of Neuronal Control of Metabolism, Max Planck Institute for Metabolism Research, Cologne, Germany
| | - Weiyi Chen
- Department of Neuronal Control of Metabolism, Max Planck Institute for Metabolism Research, Cologne, Germany
| | - Alain J de Solis
- Department of Neuronal Control of Metabolism, Max Planck Institute for Metabolism Research, Cologne, Germany
| | - Henning Fenselau
- Synaptic Transmission in Energy Homeostasis Group, Max Planck Institute for Metabolism Research, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
- Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Cologne, Germany
| | | | - Irene Cimino
- Medical Research Council Metabolic Diseases Unit, Wellcome-MRC Institute of Metabolic Science - Metabolic Research Laboratories, University of Cambridge, Cambridge, UK
| | - Sara N Kohnke
- Medical Research Council Metabolic Diseases Unit, Wellcome-MRC Institute of Metabolic Science - Metabolic Research Laboratories, University of Cambridge, Cambridge, UK
| | - Debra Rimmington
- Medical Research Council Metabolic Diseases Unit, Wellcome-MRC Institute of Metabolic Science - Metabolic Research Laboratories, University of Cambridge, Cambridge, UK
| | - Anthony P Coll
- Medical Research Council Metabolic Diseases Unit, Wellcome-MRC Institute of Metabolic Science - Metabolic Research Laboratories, University of Cambridge, Cambridge, UK
| | - Andreas Beyer
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany.
- Institute for Genetics, Faculty of Mathematics and Natural Sciences, University of Cologne, Cologne, Germany.
| | - Giles S H Yeo
- Medical Research Council Metabolic Diseases Unit, Wellcome-MRC Institute of Metabolic Science - Metabolic Research Laboratories, University of Cambridge, Cambridge, UK.
| | - Jens C Brüning
- Department of Neuronal Control of Metabolism, Max Planck Institute for Metabolism Research, Cologne, Germany.
- Synaptic Transmission in Energy Homeostasis Group, Max Planck Institute for Metabolism Research, Cologne, Germany.
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany.
- Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Cologne, Germany.
- National Center for Diabetes Research (DZD), Neuherberg, Germany.
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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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25
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Smith C, Patterson-Cross R, Woodward O, Lewis J, Chiarugi D, Merkle F, Gribble F, Reimann F, Adriaenssens A. A comparative transcriptomic analysis of glucagon-like peptide-1 receptor- and glucose-dependent insulinotropic polypeptide receptor-expressing cells in the hypothalamus. Appetite 2022; 174:106022. [PMID: 35430298 PMCID: PMC7614381 DOI: 10.1016/j.appet.2022.106022] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/21/2022] [Accepted: 03/26/2022] [Indexed: 02/02/2023]
Abstract
OBJECTIVE The hypothalamus is a key region of the brain implicated in homeostatic regulation, and is an integral centre for the control of feeding behaviour. Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are incretin hormones with potent glucoregulatory function through engagement of their respective cognate receptors, GLP-1R and GIPR. Recent evidence indicates that there is a synergistic effect of combining GIP- and GLP-1-based pharmacology on appetite and body weight. The mechanisms underlying the enhanced weight loss exhibited by GIPR/GLP-1R co-agonism are unknown. Gipr and Glp1r are expressed in the hypothalamus in both rodents and humans. To better understand incretin receptor-expressing cell populations, we compared the cell types and expression profiles of Gipr- and Glp1r-expressing hypothalamic cells using single-cell RNA sequencing. METHODS Using Glp1r-Cre or Gipr-Cre transgenic mouse lines, fluorescent reporters were introduced into either Glp1r- or Gipr-expressing cells, respectively, upon crossing with a ROSA26-EYFP reporter strain. From the hypothalami of these mice, fluorescent Glp1rEYFP+ or GiprEYFP+ cells were FACS-purified and sequenced using single-cell RNA sequencing. Transcriptomic analysis provided a survey of both non-neuronal and neuronal cells, and comparisons between Glp1rEYFP+ and GiprEYFP + populations were made. RESULTS A total of 14,091 Glp1rEYFP+ and GiprEYFP+ cells were isolated, sequenced and taken forward for bioinformatic analysis. Both Glp1rEYFP+ and GiprEYFP+ hypothalamic populations were transcriptomically highly heterogeneous, representing vascular cell types, oligodendrocytes, astrocytes, microglia, and neurons. The majority of GiprEYFP+ cells were non-neuronal, whereas the Glp1rEYFP+ population was evenly split between neuronal and non-neuronal cell types. Both Glp1rEYFP+ and GiprEYFP+ oligodendrocytes express markers for mature, myelin-forming oligodendrocytes. While mural cells are represented in both Glp1rEYFP+ and GiprEYFP+ populations, Glp1rEYFP+ mural cells are largely smooth muscle cells, while the majority of GiprEYFP+ mural cells are pericytes. The co-expression of regional markers indicate that clusters of Glp1rEYFP+ and GiprEYFP+ neurons have been isolated from the arcuate, ventromedial, lateral, tuberal, suprachiasmatic, and premammillary nuclei of the hypothalamus. CONCLUSIONS We have provided a detailed comparison of Glp1r and Gipr cells of the hypothalamus with single-cell resolution. This resource will provide mechanistic insight into how engaging Gipr- and Glp1r-expressing cells of the hypothalamus may result in changes in feeding behaviour and energy balance.
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Affiliation(s)
- Christopher Smith
- Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK
| | - Ryan Patterson-Cross
- Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK
| | - Orla Woodward
- Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK
| | - Jo Lewis
- Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK
| | - Davide Chiarugi
- Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK; Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Florian Merkle
- Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK
| | - Fiona Gribble
- Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK
| | - Frank Reimann
- Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
| | - Alice Adriaenssens
- Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
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Prevot V, Sharif A. The polygamous GnRH neuron: Astrocytic and tanycytic communication with a neuroendocrine neuronal population. J Neuroendocrinol 2022; 34:e13104. [PMID: 35233849 DOI: 10.1111/jne.13104] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 01/12/2022] [Accepted: 01/30/2022] [Indexed: 11/28/2022]
Abstract
To ensure the survival of the species, hypothalamic neuroendocrine circuits controlling fertility, which converge onto neurons producing gonadotropin-releasing hormone (GnRH), must respond to fluctuating physiological conditions by undergoing rapid and reversible structural and functional changes. However, GnRH neurons do not act alone, but through reciprocal interactions with multiple hypothalamic cell populations, including several glial and endothelial cell types. For instance, it has long been known that in the hypothalamic median eminence, where GnRH axons terminate and release their neurohormone into the pituitary portal blood circulation, morphological plasticity displayed by distal processes of tanycytes modifies their relationship with adjacent neurons as well as the spatial properties of the neurohemal junction. These alterations not only regulate the capacity of GnRH neurons to release their neurohormone, but also the activation of discrete non-neuronal pathways that mediate feedback by peripheral hormones onto the hypothalamus. Additionally, a recent breakthrough has demonstrated that GnRH neurons themselves orchestrate the establishment of their neuroendocrine circuitry during postnatal development by recruiting an entourage of newborn astrocytes that escort them into adulthood and, via signalling through gliotransmitters such as prostaglandin E2, modulate their activity and GnRH release. Intriguingly, several environmental and behavioural toxins perturb these neuron-glia interactions and consequently, reproductive maturation and fertility. Deciphering the communication between GnRH neurons and other neural cell types constituting hypothalamic neuroendocrine circuits is thus critical both to understanding physiological processes such as puberty, oestrous cyclicity and aging, and to developing novel therapeutic strategies for dysfunctions of these processes, including the effects of endocrine disruptors.
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Affiliation(s)
- Vincent Prevot
- Univ. Lille, Inserm, CHU Lille, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Lille Neuroscience & Cognition, UMR-S1172, FHU 1000 Days for Health, Lille, France
| | - Ariane Sharif
- Univ. Lille, Inserm, CHU Lille, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Lille Neuroscience & Cognition, UMR-S1172, FHU 1000 Days for Health, Lille, France
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27
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Huisman C, Norgard MA, Levasseur PR, Krasnow SM, van der Wijst MGP, Olson B, Marks DL. Critical changes in hypothalamic gene networks in response to pancreatic cancer as found by single-cell RNA sequencing. Mol Metab 2022; 58:101441. [PMID: 35031523 PMCID: PMC8851272 DOI: 10.1016/j.molmet.2022.101441] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 01/06/2022] [Accepted: 01/08/2022] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVE Cancer cachexia is a devastating chronic condition characterized by involuntary weight loss, muscle wasting, abnormal fat metabolism, anorexia, and fatigue. However, the molecular mechanisms underlying this syndrome remain poorly understood. In particular, the hypothalamus may play a central role in cachexia, given that it has direct access to peripheral signals because of its anatomical location and attenuated blood-brain barrier. Furthermore, this region has a critical role in regulating appetite and metabolism. METHODS To provide a detailed analysis of the hypothalamic response to cachexia, we performed single-cell RNA-seq combined with RNA-seq of the medial basal hypothalamus (MBH) in a mouse model for pancreatic cancer. RESULTS We found many cell type-specific changes, such as inflamed endothelial cells, stressed oligodendrocyes and both inflammatory and moderating microglia. Lcn2, a newly discovered hunger suppressing hormone, was the highest induced gene. Interestingly, cerebral treatment with LCN2 not only induced many of the observed molecular changes in cachexia but also affected gene expression in food-intake decreasing POMC neurons. In addition, we found that many of the cachexia-induced molecular changes found in the hypothalamus mimic those at the primary tumor site. CONCLUSION Our data reveal that multiple cell types in the MBH are affected by tumor-derived factors or host factors that are induced by tumor growth, leading to a marked change in the microenvironment of neurons critical for behavioral, metabolic, and neuroendocrine outputs dysregulated during cachexia. The mechanistic insights provided in this study explain many of the clinical features of cachexia and will be useful for future therapeutic development.
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Affiliation(s)
- Christian Huisman
- Papé Family Pediatric Research Institute, Oregon Health & Science University, Portland, United States; Knight Cancer Institute, Oregon Health & Science University, Portland, United States.
| | - Mason A Norgard
- Papé Family Pediatric Research Institute, Oregon Health & Science University, Portland, United States
| | - Peter R Levasseur
- Papé Family Pediatric Research Institute, Oregon Health & Science University, Portland, United States
| | - Stephanie M Krasnow
- Papé Family Pediatric Research Institute, Oregon Health & Science University, Portland, United States
| | - Monique G P van der Wijst
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Brennan Olson
- Papé Family Pediatric Research Institute, Oregon Health & Science University, Portland, United States; Medical Scientist Training Program, Oregon Health & Science University, Portland, United States
| | - Daniel L Marks
- Papé Family Pediatric Research Institute, Oregon Health & Science University, Portland, United States; Knight Cancer Institute, Oregon Health & Science University, Portland, United States; Brenden-Colson Center for Pancreatic Care, Oregon Health & Science University, Portland, United States.
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28
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Hirrlinger J, Nimmerjahn A. A perspective on astrocyte regulation of neural circuit function and animal behavior. Glia 2022; 70:1554-1580. [PMID: 35297525 PMCID: PMC9291267 DOI: 10.1002/glia.24168] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 01/19/2022] [Accepted: 02/27/2022] [Indexed: 12/16/2022]
Abstract
Studies over the past two decades have demonstrated that astrocytes are
tightly associated with neurons and play pivotal roles in neural circuit
development, operation, and adaptation in health and disease. Nevertheless,
precisely how astrocytes integrate diverse neuronal signals, modulate neural
circuit structure and function at multiple temporal and spatial scales, and
influence animal behavior or disease through aberrant excitation and molecular
output remains unclear. This Perspective discusses how new and state-of-the-art
approaches, including fluorescence indicators, opto- and chemogenetic actuators,
genetic targeting tools, quantitative behavioral assays, and computational
methods, might help resolve these longstanding questions. It also addresses
complicating factors in interpreting astrocytes’ role in neural circuit
regulation and animal behavior, such as their heterogeneity, metabolism, and
inter-glial communication. Research on these questions should provide a deeper
mechanistic understanding of astrocyte-neuron assemblies’ role in neural
circuit function, complex behaviors, and disease.
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Affiliation(s)
- Johannes Hirrlinger
- Carl-Ludwig-Institute for Physiology, Medical Faculty, University of Leipzig, Leipzig, Germany.,Department of Neurogenetics, Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Axel Nimmerjahn
- Waitt Advanced Biophotonics Center, The Salk Institute for Biological Studies, La Jolla, California
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Takeda-Uchimura Y, Nishitsuji K, Ikezaki M, Akama TO, Ihara Y, Allain F, Uchimura K. Beta3Gn-T7 Is a Keratan Sulfate β1,3 N-Acetylglucosaminyltransferase in the Adult Brain. Front Neuroanat 2022; 16:813841. [PMID: 35221933 PMCID: PMC8863611 DOI: 10.3389/fnana.2022.813841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 01/07/2022] [Indexed: 11/13/2022] Open
Abstract
Keratan sulfate (KS) glycan is covalently attached to a core protein of proteoglycans. KS is abundant in neuropils and presents densely in close proximity to the perineuronal region of the perineuronal net-positive neurons in the adult brain under physiological conditions. We previously showed that the synthesis of KS positive for the R-10G antibody in the adult brain is mediated by GlcNAc-6-sulfotransferase 3 (GlcNAc6ST3; encoded by Chst5). Deficiency in both GlcNAc6ST3 and GlcNAc6ST1, encoded by Chst2, completely abolished KS. Protein-tyrosine phosphatase receptor type z1 (Ptprz1)/phosphacan was identified as a KS scaffold. KS requires the extension of GlcNAc by β1,3 N-acetylglucosaminyltransferase (Beta3Gn-T). Members of the Beta3Gn-T family involved in the synthesis of adult brain KS have not been identified. In this study, we show by a method of gene targeting that Beta3Gn-T7, encoded by B3gnt7, is a major Beta3Gn-T for the synthesis of KS in neuropils and the perineuronal region in the adult brain. Intriguingly, the B3gnt7 gene is selectively expressed in oligodendrocyte precursor cells (OPCs) and oligodendrocytes similar to that of GlcNAc6ST3. These results indicate that Beta3Gn-T7 in oligodendrocyte lineage cells may play a role in the formation of neuropils and perineuronal nets in the adult brain through the synthesis of R-10G-positive KS-modified proteoglycan.
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Affiliation(s)
- Yoshiko Takeda-Uchimura
- Univ. Lille, CNRS, UMR 8576 – UGSF – Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | | | - Midori Ikezaki
- Department of Biochemistry, Wakayama Medical University, Wakayama, Japan
| | - Tomoya O. Akama
- Department of Pharmacology, Kansai Medical University, Osaka, Japan
| | - Yoshito Ihara
- Department of Biochemistry, Wakayama Medical University, Wakayama, Japan
| | - Fabrice Allain
- Univ. Lille, CNRS, UMR 8576 – UGSF – Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Kenji Uchimura
- Univ. Lille, CNRS, UMR 8576 – UGSF – Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
- *Correspondence: Kenji Uchimura,
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30
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Glial Modulation of Energy Balance: The Dorsal Vagal Complex Is No Exception. Int J Mol Sci 2022; 23:ijms23020960. [PMID: 35055143 PMCID: PMC8779587 DOI: 10.3390/ijms23020960] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/11/2022] [Accepted: 01/13/2022] [Indexed: 02/04/2023] Open
Abstract
The avoidance of being overweight or obese is a daily challenge for a growing number of people. The growing proportion of people suffering from a nutritional imbalance in many parts of the world exemplifies this challenge and emphasizes the need for a better understanding of the mechanisms that regulate nutritional balance. Until recently, research on the central regulation of food intake primarily focused on neuronal signaling, with little attention paid to the role of glial cells. Over the last few decades, our understanding of glial cells has changed dramatically. These cells are increasingly regarded as important neuronal partners, contributing not just to cerebral homeostasis, but also to cerebral signaling. Our understanding of the central regulation of energy balance is part of this (r)evolution. Evidence is accumulating that glial cells play a dynamic role in the modulation of energy balance. In the present review, we summarize recent data indicating that the multifaceted glial compartment of the brainstem dorsal vagal complex (DVC) should be considered in research aimed at identifying feeding-related processes operating at this level.
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31
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Clayton RW, Lovell-Badge R, Galichet C. The Properties and Functions of Glial Cell Types of the Hypothalamic Median Eminence. Front Endocrinol (Lausanne) 2022; 13:953995. [PMID: 35966104 PMCID: PMC9363565 DOI: 10.3389/fendo.2022.953995] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 06/17/2022] [Indexed: 02/06/2023] Open
Abstract
The median eminence (ME) is part of the neuroendocrine system (NES) that functions as a crucial interface between the hypothalamus and pituitary gland. The ME contains many non-neuronal cell types, including oligodendrocytes, oligodendrocyte precursor cells (OPCs), tanycytes, astrocytes, pericytes, microglia and other immune cells, which may be involved in the regulation of NES function. For example, in mice, ablation of tanycytes (a special class of ependymal glia with stem cell-like functions) results in weight gain, feeding, insulin insensitivity and increased visceral adipose, consistent with the demonstrated ability of these cells to sense and transport both glucose and leptin, and to differentiate into neurons that control feeding and metabolism in the hypothalamus. To give a further example, OPCs in the ME of mice have been shown to rapidly respond to dietary signals, in turn controlling composition of the extracellular matrix in the ME, derived from oligodendrocyte-lineage cells, which may contribute to the previously described role of these cells in actively maintaining leptin-receptor-expressing dendrites in the ME. In this review, we explore and discuss recent advances such as these, that have developed our understanding of how the various cell types of the ME contribute to its function in the NES as the interface between the hypothalamus and pituitary gland. We also highlight avenues of future research which promise to uncover additional functions of the ME and the glia, stem and progenitor cells it contains.
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32
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Hines JH. Evolutionary Origins of the Oligodendrocyte Cell Type and Adaptive Myelination. Front Neurosci 2021; 15:757360. [PMID: 34924932 PMCID: PMC8672417 DOI: 10.3389/fnins.2021.757360] [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: 08/12/2021] [Accepted: 10/29/2021] [Indexed: 12/23/2022] Open
Abstract
Oligodendrocytes are multifunctional central nervous system (CNS) glia that are essential for neural function in gnathostomes. The evolutionary origins and specializations of the oligodendrocyte cell type are among the many remaining mysteries in glial biology and neuroscience. The role of oligodendrocytes as CNS myelinating glia is well established, but recent studies demonstrate that oligodendrocytes also participate in several myelin-independent aspects of CNS development, function, and maintenance. Furthermore, many recent studies have collectively advanced our understanding of myelin plasticity, and it is now clear that experience-dependent adaptations to myelination are an additional form of neural plasticity. These observations beg the questions of when and for which functions the ancestral oligodendrocyte cell type emerged, when primitive oligodendrocytes evolved new functionalities, and the genetic changes responsible for these evolutionary innovations. Here, I review recent findings and propose working models addressing the origins and evolution of the oligodendrocyte cell type and adaptive myelination. The core gene regulatory network (GRN) specifying the oligodendrocyte cell type is also reviewed as a means to probe the existence of oligodendrocytes in basal vertebrates and chordate invertebrates.
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Affiliation(s)
- Jacob H. Hines
- Biology Department, Winona State University, Winona, MN, United States
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33
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Zhang X, Huang N, Xiao L, Wang F, Li T. Replenishing the Aged Brains: Targeting Oligodendrocytes and Myelination? Front Aging Neurosci 2021; 13:760200. [PMID: 34899272 PMCID: PMC8656359 DOI: 10.3389/fnagi.2021.760200] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 11/02/2021] [Indexed: 11/13/2022] Open
Abstract
Aging affects almost all the aspects of brain functions, but the mechanisms remain largely undefined. Increasing number of literatures have manifested the important role of glial cells in regulating the aging process. Oligodendroglial lineage cell is a major type of glia in central nervous system (CNS), composed of mature oligodendrocytes (OLs), and oligodendroglia precursor cells (OPCs). OLs produce myelin sheaths that insulate axons and provide metabolic support to meet the energy demand. OPCs maintain the population throughout lifetime with the abilities to proliferate and differentiate into OLs. Increasing evidence has shown that oligodendroglial cells display active dynamics in adult and aging CNS, which is extensively involved in age-related brain function decline in the elderly. In this review, we summarized present knowledge about dynamic changes of oligodendroglial lineage cells during normal aging and discussed their potential roles in age-related functional decline. Especially, focused on declined myelinogenesis during aging and underlying mechanisms. Clarifying those oligodendroglial changes and their effects on neurofunctional decline may provide new insights in understanding aging associated brain function declines.
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Affiliation(s)
- Xi Zhang
- Department of Histology and Embryology, Army Medical University (Third Military Medical University), Chongqing, China
- Department of Ophthalmology, The General Hospital of Western Theater Command, Chengdu, China
| | - Nanxin Huang
- Department of Histology and Embryology, Army Medical University (Third Military Medical University), Chongqing, China
| | - Lan Xiao
- Department of Histology and Embryology, Army Medical University (Third Military Medical University), Chongqing, China
| | - Fei Wang
- Department of Histology and Embryology, Army Medical University (Third Military Medical University), Chongqing, China
| | - Tao Li
- Department of Histology and Embryology, Army Medical University (Third Military Medical University), Chongqing, China
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34
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Crapser JD, Arreola MA, Tsourmas KI, Green KN. Microglia as hackers of the matrix: sculpting synapses and the extracellular space. Cell Mol Immunol 2021; 18:2472-2488. [PMID: 34413489 PMCID: PMC8546068 DOI: 10.1038/s41423-021-00751-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 07/26/2021] [Indexed: 02/08/2023] Open
Abstract
Microglia shape the synaptic environment in health and disease, but synapses do not exist in a vacuum. Instead, pre- and postsynaptic terminals are surrounded by extracellular matrix (ECM), which together with glia comprise the four elements of the contemporary tetrapartite synapse model. While research in this area is still just beginning, accumulating evidence points toward a novel role for microglia in regulating the ECM during normal brain homeostasis, and such processes may, in turn, become dysfunctional in disease. As it relates to synapses, microglia are reported to modify the perisynaptic matrix, which is the diffuse matrix that surrounds dendritic and axonal terminals, as well as perineuronal nets (PNNs), specialized reticular formations of compact ECM that enwrap neuronal subsets and stabilize proximal synapses. The interconnected relationship between synapses and the ECM in which they are embedded suggests that alterations in one structure necessarily affect the dynamics of the other, and microglia may need to sculpt the matrix to modify the synapses within. Here, we provide an overview of the microglial regulation of synapses, perisynaptic matrix, and PNNs, propose candidate mechanisms by which these structures may be modified, and present the implications of such modifications in normal brain homeostasis and in disease.
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Affiliation(s)
- Joshua D. Crapser
- grid.266093.80000 0001 0668 7243Department of Neurobiology and Behavior, University of California, Irvine, CA USA
| | - Miguel A. Arreola
- grid.266093.80000 0001 0668 7243Department of Neurobiology and Behavior, University of California, Irvine, CA USA
| | - Kate I. Tsourmas
- grid.266093.80000 0001 0668 7243Department of Neurobiology and Behavior, University of California, Irvine, CA USA
| | - Kim N. Green
- grid.266093.80000 0001 0668 7243Department of Neurobiology and Behavior, University of California, Irvine, CA USA
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