1
|
Rosatti MR, Gargaglioni LH, Dias MB. Lateral hypothalamic astrocytes contribute to the hypercapnic chemoreflex in a light-dark cycle-dependent manner in unanesthetized rats. Respir Physiol Neurobiol 2024; 331:104352. [PMID: 39299615 DOI: 10.1016/j.resp.2024.104352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2024] [Revised: 09/13/2024] [Accepted: 09/16/2024] [Indexed: 09/22/2024]
Abstract
Brainstem astrocytes are important for CO2/H+ chemoreception. Lateral Hypothalamus/Perifornicial Area (LH/PFA) neurons have an excitatory effect on the ventilatory response to CO2, however the role of the astrocytes is unknown. We hypothesized that LH/PFA astrocytes play an excitatory role in the hypercapnic ventilatory response in a sleep-wake and light-dark cycles-dependent manner. We manipulated the activity of astrocytes in the LH/PFA of male Wistar rats through microinjection of Fluorocitrate (Fct), which selectively affects astrocytes, inducing the exocytosis of gliotransmitters. We investigated the effects of intra-LH/PFA Fct microinjection on resting breathing and ventilatory responses to hypercapnia and hypoxia during wakefulness and NREM sleep, in the light and dark phases. Fct increased ventilation during hypercapnia but not during room air or hypoxia. The hypercapnic chemoreflex was increased exclusively during the dark-active phase during both, wakefulness and NREM sleep, indicating that LH/PFA astrocytes play an excitatory role in hypercapnic ventilatory response in a light-dark cycle-dependent manner.
Collapse
Affiliation(s)
- Marcelo Rafanelli Rosatti
- Department of Structural and Functional Biology, Physiology, Institute of Bioscience, Sao Paulo State University-UNESP, Botucatu, SP, Brazil. Botucatu, SP, Brazil.
| | - Luciane H Gargaglioni
- Department of Animal Morphology and Physiology, Sao Paulo State University-FCAV, Jaboticabal, SP, Brazil.
| | - Mirela B Dias
- Department of Structural and Functional Biology, Physiology, Institute of Bioscience, Sao Paulo State University-UNESP, Botucatu, SP, Brazil. Botucatu, SP, Brazil.
| |
Collapse
|
2
|
Sharif A, Prevot V. Astrogenesis in the hypothalamus: A life-long process contributing to the development and plasticity of neuroendocrine networks. Front Neuroendocrinol 2024; 75:101154. [PMID: 39226950 DOI: 10.1016/j.yfrne.2024.101154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2024] [Revised: 08/27/2024] [Accepted: 08/28/2024] [Indexed: 09/05/2024]
Abstract
Astrocytes are now recognized as integral components of neural circuits, regulating their maturation, activity and plasticity. Neuroendocrinology has provided fertile ground for revealing the diverse strategies used by astrocytes to regulate the physiological and behavioural outcomes of neural circuit activity in response to internal and environmental inputs. However, the development of astrocytes in the hypothalamus has received much less attention than in other brain regions such as the cerebral cortex and spinal cord. In this review, we synthesize our current knowledge of astrogenesis in the hypothalamus across various life stages. A distinctive feature of hypothalamic astrogenesis is that it persists all throughout lifespan, and involves multiple cellular sources corresponding to radial glial cells during early development, followed by tanycytes, parenchymal progenitors and locally dividing astrocytes. Astrogenesis in the hypothalamus is closely coordinated with the maturation of hypothalamic neurons. This coordination is exemplified by recent findings in neurons producing gonadotropin-releasing hormone, which actively shape their astroglial environment during infancy to integrate functionally into their neural network and facilitate sexual maturation, a process vulnerable to endocrine disruption. While hypothalamic astrogenesis shares common principles with other brain regions, it also exhibits specific features in its dynamics and regulation, both at the inter- and intra-regional levels. These unique properties emphasize the importance of further exploration. Additionally, we discuss the experimental strategies used to assess astrogenesis in the hypothalamus and their potential bias and limitations. Understanding the mechanisms of hypothalamic astrogenesis throughout life will be crucial for comprehending the development and function of the hypothalamus under both physiological and pathological conditions.
Collapse
Affiliation(s)
- Ariane Sharif
- Univ. Lille, Inserm, CHU Lille, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Lille Neuroscience & Cognition, UMR-S 1172, FHU 1000 Days for Health, Lille, France.
| | - Vincent Prevot
- Univ. Lille, Inserm, CHU Lille, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Lille Neuroscience & Cognition, UMR-S 1172, FHU 1000 Days for Health, Lille, France.
| |
Collapse
|
3
|
Wolff C, John D, Winkler U, Hochmuth L, Hirrlinger J, Köhler S. Insulin and leptin acutely modulate the energy metabolism of primary hypothalamic and cortical astrocytes. J Neurochem 2024. [PMID: 39175305 DOI: 10.1111/jnc.16211] [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: 03/27/2024] [Revised: 08/06/2024] [Accepted: 08/11/2024] [Indexed: 08/24/2024]
Abstract
Astrocytes constitute a heterogeneous cell population within the brain, contributing crucially to brain homeostasis and playing an important role in overall brain function. Their function and metabolism are not only regulated by local signals, for example, from nearby neurons, but also by long-range signals such as hormones. Thus, two prominent hormones primarily known for regulating the energy balance of the whole organism, insulin, and leptin, have been reported to also impact astrocytes within the brain. In this study, we investigated the acute regulation of astrocytic metabolism by these hormones in cultured astrocytes prepared from the mouse cortex and hypothalamus, a pivotal region in the context of nutritional regulation. Utilizing genetically encoded, fluorescent nanosensors, the cytosolic concentrations of glucose, lactate, and ATP, along with glycolytic rate and the NADH/NAD+ redox state were measured. Under basal conditions, differences between the two populations of astrocytes were observed for glucose and lactate concentrations as well as the glycolytic rate. Additionally, astrocytic metabolism responded to insulin and leptin in both brain regions, with some unique characteristics for each cell population. Finally, both hormones influenced how cells responded to elevated extracellular levels of potassium ions, a common indicator of neuronal activity. In summary, our study provides evidence that insulin and leptin acutely regulate astrocytic metabolism within minutes. Additionally, while astrocytes from the hypothalamus and cortex share similarities in their metabolism, they also exhibit distinct properties, further underscoring the growing recognition of astrocyte heterogeneity.
Collapse
Affiliation(s)
- Christopher Wolff
- Faculty of Medicine, Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
| | - Dorit John
- Faculty of Medicine, Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
- Medical Department II-Division of Oncology, Gastroenterology, Hepatology and Pneumology, University of Leipzig Medical Center, Leipzig, Germany
| | - Ulrike Winkler
- Faculty of Medicine, Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
| | - Luise Hochmuth
- Faculty of Medicine, Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
| | - Johannes Hirrlinger
- Faculty of Medicine, Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
- Department of Neurogenetics, Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Susanne Köhler
- Faculty of Medicine, Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
- Sächsisches Krankenhaus Altscherbitz, Clinic for Neurology, Schkeuditz, Germany
| |
Collapse
|
4
|
Fernández-Moncada I, Lavanco G, Fundazuri UB, Bollmohr N, Mountadem S, Dalla Tor T, Hachaguer P, Julio-Kalajzic F, Gisquet D, Serrat R, Bellocchio L, Cannich A, Fortunato-Marsol B, Nasu Y, Campbell RE, Drago F, Cannizzaro C, Ferreira G, Bouzier-Sore AK, Pellerin L, Bolaños JP, Bonvento G, Barros LF, Oliet SHR, Panatier A, Marsicano G. A lactate-dependent shift of glycolysis mediates synaptic and cognitive processes in male mice. Nat Commun 2024; 15:6842. [PMID: 39122700 PMCID: PMC11316019 DOI: 10.1038/s41467-024-51008-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2024] [Accepted: 07/16/2024] [Indexed: 08/12/2024] Open
Abstract
Astrocytes control brain activity via both metabolic processes and gliotransmission, but the physiological links between these functions are scantly known. Here we show that endogenous activation of astrocyte type-1 cannabinoid (CB1) receptors determines a shift of glycolysis towards the lactate-dependent production of D-serine, thereby gating synaptic and cognitive functions in male mice. Mutant mice lacking the CB1 receptor gene in astrocytes (GFAP-CB1-KO) are impaired in novel object recognition (NOR) memory. This phenotype is rescued by the gliotransmitter D-serine, by its precursor L-serine, and also by lactate and 3,5-DHBA, an agonist of the lactate receptor HCAR1. Such lactate-dependent effect is abolished when the astrocyte-specific phosphorylated-pathway (PP), which diverts glycolysis towards L-serine synthesis, is blocked. Consistently, lactate and 3,5-DHBA promoted the co-agonist binding site occupancy of CA1 post-synaptic NMDA receptors in hippocampal slices in a PP-dependent manner. Thus, a tight cross-talk between astrocytic energy metabolism and gliotransmission determines synaptic and cognitive processes.
Collapse
Affiliation(s)
| | - Gianluca Lavanco
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-33000, Bordeaux, France
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, Catania, Italy
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties, ''G. D'Alessandro", University of Palermo, Palermo, Italy
| | - Unai B Fundazuri
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-33000, Bordeaux, France
| | - Nasrin Bollmohr
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-33000, Bordeaux, France
| | - Sarah Mountadem
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-33000, Bordeaux, France
| | - Tommaso Dalla Tor
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-33000, Bordeaux, France
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, Catania, Italy
| | - Pauline Hachaguer
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-33000, Bordeaux, France
| | | | - Doriane Gisquet
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-33000, Bordeaux, France
| | - Roman Serrat
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-33000, Bordeaux, France
- Univ. Bordeaux, INRAE, Bordeaux INP, NutriNeuro, UMR 1286, F-33000, Bordeaux, France
| | - Luigi Bellocchio
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-33000, Bordeaux, France
| | - Astrid Cannich
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-33000, Bordeaux, France
| | | | - Yusuke Nasu
- Department of Chemistry, School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- PRESTO, Japan Science and Technology Agency, Chiyoda-ku, Tokyo, Japan
| | - Robert E Campbell
- Department of Chemistry, School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- CERVO Brain Research Center and Department of Biochemistry, Microbiology, and Bioinformatics, Université Laval, Québec City, QC, Canada
| | - Filippo Drago
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, Catania, Italy
| | - Carla Cannizzaro
- Department of Biomedicine, Neuroscience and Advanced Diagnostics, University of Palermo, Palermo, Italy
| | - Guillaume Ferreira
- Univ. Bordeaux, INRAE, Bordeaux INP, NutriNeuro, UMR 1286, F-33000, Bordeaux, France
| | - Anne-Karine Bouzier-Sore
- Univ. Bordeaux, CNRS, Centre de Résonance Magnétique des Systèmes Biologiques, UMR 5536, F-33000, Bordeaux, France
| | - Luc Pellerin
- Université de Poitiers et CHU de Poitiers, INSERM, IRMETIST, U1313, Poitiers, France
| | - Juan P Bolaños
- Institute of Functional Biology and Genomics (IBFG), Universidad de Salamanca, CSIC, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), Hospital Universitario de Salamanca, Salamanca, Spain
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Madrid, Spain
| | - Gilles Bonvento
- Universite Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire des Maladies Neurodegeneratives, Fontenay-aux-Roses, France
| | - L Felipe Barros
- Centro de Estudios Cientificos, Valdivia, Chile
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Valdivia, Chile
| | - Stephane H R Oliet
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-33000, Bordeaux, France
| | - Aude Panatier
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-33000, Bordeaux, France
| | - Giovanni Marsicano
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-33000, Bordeaux, France.
| |
Collapse
|
5
|
Araki S, Onishi I, Ikoma Y, Matsui K. Astrocyte switch to the hyperactive mode. Glia 2024; 72:1418-1434. [PMID: 38591259 DOI: 10.1002/glia.24537] [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: 01/23/2024] [Revised: 03/29/2024] [Accepted: 03/31/2024] [Indexed: 04/10/2024]
Abstract
Increasing pieces of evidence have suggested that astrocyte function has a strong influence on neuronal activity and plasticity, both in physiological and pathophysiological situations. In epilepsy, astrocytes have been shown to respond to epileptic neuronal seizures; however, whether they can act as a trigger for seizures has not been determined. Here, using the copper implantation method, spontaneous neuronal hyperactivity episodes were reliably induced during the week following implantation. With near 24-h continuous recording for over 1 week of the local field potential with in vivo electrophysiology and astrocyte cytosolic Ca2+ with the fiber photometry method, spontaneous occurrences of seizure episodes were captured. Approximately 1 day after the implantation, isolated aberrant astrocyte Ca2+ events were often observed before they were accompanied by neuronal hyperactivity, suggesting the role of astrocytes in epileptogenesis. Within a single developed episode, astrocyte Ca2+ increase preceded the neuronal hyperactivity by ~20 s, suggesting that actions originating from astrocytes could be the trigger for the occurrence of epileptic seizures. Astrocyte-specific stimulation by channelrhodopsin-2 or deep-brain direct current stimulation was capable of inducing neuronal hyperactivity. Injection of an astrocyte-specific metabolic inhibitor, fluorocitrate, was able to significantly reduce the magnitude of spontaneously occurring neuronal hyperactivity. These results suggest that astrocytes have a role in triggering individual seizures and the reciprocal astrocyte-neuron interactions likely amplify and exacerbate seizures. Therefore, future epilepsy treatment could be targeted at astrocytes to achieve epilepsy control.
Collapse
Affiliation(s)
- Shun Araki
- Super-network Brain Physiology, Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - Ichinosuke Onishi
- Super-network Brain Physiology, Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - Yoko Ikoma
- Super-network Brain Physiology, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Ko Matsui
- Super-network Brain Physiology, Graduate School of Medicine, Tohoku University, Sendai, Japan
- Super-network Brain Physiology, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| |
Collapse
|
6
|
Juvenal G, Higa GSV, Bonfim Marques L, Tessari Zampieri T, Costa Viana FJ, Britto LR, Tang Y, Illes P, di Virgilio F, Ulrich H, de Pasquale R. Regulation of GABAergic neurotransmission by purinergic receptors in brain physiology and disease. Purinergic Signal 2024:10.1007/s11302-024-10034-x. [PMID: 39046648 DOI: 10.1007/s11302-024-10034-x] [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: 02/28/2024] [Accepted: 06/19/2024] [Indexed: 07/25/2024] Open
Abstract
Purinergic receptors regulate the processing of neural information in the hippocampus and cerebral cortex, structures related to cognitive functions. These receptors are activated when astrocytic and neuronal populations release adenosine triphosphate (ATP) in an autocrine and paracrine manner, following sustained patterns of neuronal activity. The modulation by these receptors of GABAergic transmission has only recently been studied. Through their ramifications, astrocytes and GABAergic interneurons reach large groups of excitatory pyramidal neurons. Their inhibitory effect establishes different synchronization patterns that determine gamma frequency rhythms, which characterize neural activities related to cognitive processes. During early life, GABAergic-mediated synchronization of excitatory signals directs the experience-driven maturation of cognitive development, and dysfunctions concerning this process have been associated with neurological and neuropsychiatric diseases. Purinergic receptors timely modulate GABAergic control over ongoing neural activity and deeply affect neural processing in the hippocampal and neocortical circuitry. Stimulation of A2 receptors increases GABA release from presynaptic terminals, leading to a considerable reduction in neuronal firing of pyramidal neurons. A1 receptors inhibit GABAergic activity but only act in the early postnatal period when GABA produces excitatory signals. P2X and P2Y receptors expressed in pyramidal neurons reduce the inhibitory tone by blocking GABAA receptors. Finally, P2Y receptor activation elicits depolarization of GABAergic neurons and increases GABA release, thus favoring the emergence of gamma oscillations. The present review provides an overall picture of purinergic influence on GABAergic transmission and its consequences on neural processing, extending the discussion to receptor subtypes and their involvement in the onset of brain disorders, including epilepsy and Alzheimer's disease.
Collapse
Affiliation(s)
- Guilherme Juvenal
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, SP, Brazil
| | - Guilherme Shigueto Vilar Higa
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, SP, Brazil
- Department of Biophysics and Physiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Lucas Bonfim Marques
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, SP, Brazil
| | - Thais Tessari Zampieri
- Department of Biophysics and Physiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Felipe José Costa Viana
- Department of Biophysics and Physiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Luiz R Britto
- Department of Biophysics and Physiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Yong Tang
- International Joint Research Centre On Purinergic Signalling, Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China
- School of Health and Rehabilitation, Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China
| | - Peter Illes
- International Joint Research Centre On Purinergic Signalling, Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China
- School of Health and Rehabilitation, Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China
- Rudolf Boehm Institute for Pharmacology and Toxicology, University of Leipzig, 04107, Leipzig, Germany
| | | | - Henning Ulrich
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, SP, Brazil.
- International Joint Research Centre On Purinergic Signalling, Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China.
| | - Roberto de Pasquale
- Department of Biophysics and Physiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
| |
Collapse
|
7
|
Moretti J, Rodger J. Working toward an integrated plasticity/network framework for repetitive transcranial magnetic stimulation to inform tailored treatments. Neural Regen Res 2024; 19:1423-1424. [PMID: 38051878 PMCID: PMC10883519 DOI: 10.4103/1673-5374.387990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 09/28/2023] [Indexed: 12/07/2023] Open
Affiliation(s)
- Jessica Moretti
- Experimental and Regenerative Neurosciences, School of Biological Sciences, University of Western Australia, Crawley, WA, Australia
- Brain Plasticity Lab, Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia
| | - Jennifer Rodger
- Experimental and Regenerative Neurosciences, School of Biological Sciences, University of Western Australia, Crawley, WA, Australia
- Brain Plasticity Lab, Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia
| |
Collapse
|
8
|
Barsanti S, Viana JF, Veiga A, Machado JL, Abreu DS, Dias JD, Monteiro S, Silva NA, Pinto L, Oliveira JF. Assessing Different Histological Preparations for Reconstruction of Astrocyte Tridimensional Structure. Cells 2024; 13:969. [PMID: 38891101 PMCID: PMC11171983 DOI: 10.3390/cells13110969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 05/20/2024] [Accepted: 05/31/2024] [Indexed: 06/21/2024] Open
Abstract
Astrocytes are ubiquitous in the brain and spinal cord and display a complex morphology important for the local interactions with neighboring cells, resulting in the modulation of circuit function. Thus, studies focusing on astrocyte physiology in the healthy and diseased brain generally present analyses of astrocytic structure. The labeling method used to visualize the astrocytic structure defines the morphological level to observe and may vary depending on the anatomical sub-regions. The method choice may significantly affect our understanding of their structural diversity. The main goal of this work was to identify a straightforward and efficient protocol for labeling and reconstructing a detailed astrocytic structure to apply and validate in different brain tissue preparations across laboratories. For that, we explored different tissue processing protocols before GFAP labeling to determine the most effective method for reconstructing astrocytic backbones in the mouse hippocampus. Our results show that the reconstruction of astrocytic structure in vibratome sections labeled by free-floating immunofluorescence protocol provides a more practical method to achieve a higher level of detail and arbor complexity in astrocyte backbone reconstruction. Free-floating immunofluorescence labeling is the most reliable method for obtaining better antibody penetration and more detailed astrocyte structure. Finally, we also show that introducing an antigen retrieval step appears useful for visualizing more complete structural details.
Collapse
Affiliation(s)
- Sara Barsanti
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (S.B.); (J.F.V.); (A.V.); (J.L.M.); (D.S.A.); (J.D.D.); (S.M.); (N.A.S.); (L.P.)
- ICVS/3B’s-PT Government Associate Laboratory, 4710-057 Braga/Guimarães, Portugal
| | - João Filipe Viana
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (S.B.); (J.F.V.); (A.V.); (J.L.M.); (D.S.A.); (J.D.D.); (S.M.); (N.A.S.); (L.P.)
- ICVS/3B’s-PT Government Associate Laboratory, 4710-057 Braga/Guimarães, Portugal
| | - Alexandra Veiga
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (S.B.); (J.F.V.); (A.V.); (J.L.M.); (D.S.A.); (J.D.D.); (S.M.); (N.A.S.); (L.P.)
- ICVS/3B’s-PT Government Associate Laboratory, 4710-057 Braga/Guimarães, Portugal
| | - João Luís Machado
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (S.B.); (J.F.V.); (A.V.); (J.L.M.); (D.S.A.); (J.D.D.); (S.M.); (N.A.S.); (L.P.)
- ICVS/3B’s-PT Government Associate Laboratory, 4710-057 Braga/Guimarães, Portugal
| | - Daniela Sofia Abreu
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (S.B.); (J.F.V.); (A.V.); (J.L.M.); (D.S.A.); (J.D.D.); (S.M.); (N.A.S.); (L.P.)
- ICVS/3B’s-PT Government Associate Laboratory, 4710-057 Braga/Guimarães, Portugal
| | - José Duarte Dias
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (S.B.); (J.F.V.); (A.V.); (J.L.M.); (D.S.A.); (J.D.D.); (S.M.); (N.A.S.); (L.P.)
- ICVS/3B’s-PT Government Associate Laboratory, 4710-057 Braga/Guimarães, Portugal
| | - Susana Monteiro
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (S.B.); (J.F.V.); (A.V.); (J.L.M.); (D.S.A.); (J.D.D.); (S.M.); (N.A.S.); (L.P.)
- ICVS/3B’s-PT Government Associate Laboratory, 4710-057 Braga/Guimarães, Portugal
| | - Nuno A. Silva
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (S.B.); (J.F.V.); (A.V.); (J.L.M.); (D.S.A.); (J.D.D.); (S.M.); (N.A.S.); (L.P.)
- ICVS/3B’s-PT Government Associate Laboratory, 4710-057 Braga/Guimarães, Portugal
| | - Luísa Pinto
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (S.B.); (J.F.V.); (A.V.); (J.L.M.); (D.S.A.); (J.D.D.); (S.M.); (N.A.S.); (L.P.)
- ICVS/3B’s-PT Government Associate Laboratory, 4710-057 Braga/Guimarães, Portugal
| | - João Filipe Oliveira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (S.B.); (J.F.V.); (A.V.); (J.L.M.); (D.S.A.); (J.D.D.); (S.M.); (N.A.S.); (L.P.)
- ICVS/3B’s-PT Government Associate Laboratory, 4710-057 Braga/Guimarães, Portugal
- IPCA-EST-2Ai, Applied Artificial Intelligence Laboratory, Polytechnic Institute of Cávado and Ave, Campus of IPCA, 4750-810 Barcelos, Portugal
| |
Collapse
|
9
|
Denker N, Dringen R. Modulation of Pyruvate Export and Extracellular Pyruvate Concentration in Primary Astrocyte Cultures. Neurochem Res 2024; 49:1331-1346. [PMID: 38376749 PMCID: PMC10991036 DOI: 10.1007/s11064-024-04120-0] [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: 11/10/2023] [Revised: 02/02/2024] [Accepted: 02/02/2024] [Indexed: 02/21/2024]
Abstract
Astrocyte-derived pyruvate is considered to have neuroprotective functions. In order to investigate the processes that are involved in astrocytic pyruvate release, we used primary rat astrocyte cultures as model system. Depending on the incubation conditions and medium composition, astrocyte cultures established extracellular steady state pyruvate concentrations in the range between 150 µM and 300 µM. During incubations for up to 2 weeks in DMEM culture medium, the extracellular pyruvate concentration remained almost constant for days, while the extracellular lactate concentration increased continuously during the incubation into the millimolar concentration range as long as glucose was present. In an amino acid-free incubation buffer, glucose-fed astrocytes released pyruvate with an initial rate of around 60 nmol/(h × mg) and after around 5 h an almost constant extracellular pyruvate concentration was established that was maintained for several hours. Extracellular pyruvate accumulation was also observed, if glucose had been replaced by mannose, fructose, lactate or alanine. Glucose-fed astrocyte cultures established similar extracellular steady state concentrations of pyruvate by releasing pyruvate into pyruvate-free media or by consuming excess of extracellular pyruvate. Inhibition of the monocarboxylate transporter MCT1 by AR-C155858 lowered extracellular pyruvate accumulation, while inhibition of mitochondrial pyruvate uptake by UK5099 increased the extracellular pyruvate concentration. Finally, the presence of the uncoupler BAM15 or of the respiratory chain inhibitor antimycin A almost completely abolished extracellular pyruvate accumulation. The data presented demonstrate that cultured astrocytes establish a transient extracellular steady state concentration of pyruvate which is strongly affected by modulation of the mitochondrial pyruvate metabolism.
Collapse
Affiliation(s)
- Nadine Denker
- Centre for Biomolecular Interactions Bremen, Faculty 2 (Biology/Chemistry) and Centre for Environmental Research and Sustainable Technologies, University of Bremen, P.O. Box 330440, 28334, Bremen, Germany
| | - Ralf Dringen
- Centre for Biomolecular Interactions Bremen, Faculty 2 (Biology/Chemistry) and Centre for Environmental Research and Sustainable Technologies, University of Bremen, P.O. Box 330440, 28334, Bremen, Germany.
| |
Collapse
|
10
|
Refaeli R, Kreisel T, Yaish TR, Groysman M, Goshen I. Astrocytes control recent and remote memory strength by affecting the recruitment of the CA1→ACC projection to engrams. Cell Rep 2024; 43:113943. [PMID: 38483907 PMCID: PMC10995765 DOI: 10.1016/j.celrep.2024.113943] [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: 10/08/2023] [Revised: 01/14/2024] [Accepted: 02/23/2024] [Indexed: 04/02/2024] Open
Abstract
The maturation of engrams from recent to remote time points involves the recruitment of CA1 neurons projecting to the anterior cingulate cortex (CA1→ACC). Modifications of G-protein-coupled receptor pathways in CA1 astrocytes affect recent and remote recall in seemingly contradictory ways. To address this inconsistency, we manipulated these pathways in astrocytes during memory acquisition and tagged c-Fos-positive engram cells and CA1→ACC cells during recent and remote recall. The behavioral results were coupled with changes in the recruitment of CA1→ACC projection cells to the engram: Gq pathway activation in astrocytes caused enhancement of recent recall alone and was accompanied by earlier recruitment of CA1→ACC projecting cells to the engram. In contrast, Gi pathway activation in astrocytes resulted in the impairment of only remote recall, and CA1→ACC projecting cells were not recruited during remote memory. Finally, we provide a simple working model, hypothesizing that Gq and Gi pathway activation affect memory differently, by modulating the same mechanism: CA1→ACC projection.
Collapse
Affiliation(s)
- Ron Refaeli
- Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Tirzah Kreisel
- Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | | | - Maya Groysman
- ELSC Vector Core Facility, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Inbal Goshen
- Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
| |
Collapse
|
11
|
Li B, Deng S, Jiang H, Zhu W, Zhuo B, Du Y, Meng Z. The mechanistic effects of acupuncture in rodent neurodegenerative disease models: a literature review. Front Neurosci 2024; 18:1323555. [PMID: 38500484 PMCID: PMC10944972 DOI: 10.3389/fnins.2024.1323555] [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: 10/19/2023] [Accepted: 02/20/2024] [Indexed: 03/20/2024] Open
Abstract
Neurodegenerative diseases refer to a battery of medical conditions that affect the survival and function of neurons in the brain, which are mainly presented with progressive loss of cognitive and/or motor function. Acupuncture showed benign effects in improving neurological deficits, especially on movement and cognitive function impairment. Here, we reviewed the therapeutic mechanisms of acupuncture at the neural circuit level in movement and cognition disorders, summarizing the influence of acupuncture in the dopaminergic system, glutamatergic system, γ-amino butyric acid-ergic (GABAergic) system, serotonergic system, cholinergic system, and glial cells at the circuit and synaptic levels. These findings can provide targets for clinical treatment and perspectives for further studies.
Collapse
Affiliation(s)
- Boxuan Li
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Shizhe Deng
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Hailun Jiang
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Weiming Zhu
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Bifang Zhuo
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Yuzheng Du
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Zhihong Meng
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
| |
Collapse
|
12
|
Czyżewski W, Mazurek M, Sakwa L, Szymoniuk M, Pham J, Pasierb B, Litak J, Czyżewska E, Turek M, Piotrowski B, Torres K, Rola R. Astroglial Cells: Emerging Therapeutic Targets in the Management of Traumatic Brain Injury. Cells 2024; 13:148. [PMID: 38247839 PMCID: PMC10813911 DOI: 10.3390/cells13020148] [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: 11/29/2023] [Revised: 12/20/2023] [Accepted: 12/20/2023] [Indexed: 01/23/2024] Open
Abstract
Traumatic Brain Injury (TBI) represents a significant health concern, necessitating advanced therapeutic interventions. This detailed review explores the critical roles of astrocytes, key cellular constituents of the central nervous system (CNS), in both the pathophysiology and possible rehabilitation of TBI. Following injury, astrocytes exhibit reactive transformations, differentiating into pro-inflammatory (A1) and neuroprotective (A2) phenotypes. This paper elucidates the interactions of astrocytes with neurons, their role in neuroinflammation, and the potential for their therapeutic exploitation. Emphasized strategies encompass the utilization of endocannabinoid and calcium signaling pathways, hormone-based treatments like 17β-estradiol, biological therapies employing anti-HBGB1 monoclonal antibodies, gene therapy targeting Connexin 43, and the innovative technique of astrocyte transplantation as a means to repair damaged neural tissues.
Collapse
Affiliation(s)
- Wojciech Czyżewski
- Department of Didactics and Medical Simulation, Medical University of Lublin, 20-954 Lublin, Poland;
- Department of Neurosurgery and Pediatric Neurosurgery, Medical University of Lublin, 20-954 Lublin, Poland; (M.M.); (R.R.)
| | - Marek Mazurek
- Department of Neurosurgery and Pediatric Neurosurgery, Medical University of Lublin, 20-954 Lublin, Poland; (M.M.); (R.R.)
| | - Leon Sakwa
- Student Scientific Society, Kazimierz Pulaski University of Radom, 26-600 Radom, Poland;
| | - Michał Szymoniuk
- Student Scientific Association, Department of Neurosurgery and Pediatric Neurosurgery, Medical University of Lublin, 20-954 Lublin, Poland;
| | - Jennifer Pham
- Student Scientific Society, Medical University of Lublin, 20-954 Lublin, Poland; (J.P.); (M.T.)
| | - Barbara Pasierb
- Department of Dermatology, Radom Specialist Hospital, 26-600 Radom, Poland;
| | - Jakub Litak
- Department of Clinical Immunology, Medical University of Lublin, 20-954 Lublin, Poland;
| | - Ewa Czyżewska
- Department of Otolaryngology, Mazovian Specialist Hospital, 26-617 Radom, Poland;
| | - Michał Turek
- Student Scientific Society, Medical University of Lublin, 20-954 Lublin, Poland; (J.P.); (M.T.)
| | - Bartłomiej Piotrowski
- Institute of Automatic Control and Robotics, Warsaw University of Technology, 00-661 Warsaw, Poland;
| | - Kamil Torres
- Department of Didactics and Medical Simulation, Medical University of Lublin, 20-954 Lublin, Poland;
| | - Radosław Rola
- Department of Neurosurgery and Pediatric Neurosurgery, Medical University of Lublin, 20-954 Lublin, Poland; (M.M.); (R.R.)
| |
Collapse
|
13
|
Rivera-Villaseñor A, Higinio-Rodríguez F, López-Hidalgo M. Astrocytes in Pain Perception: A Systems Neuroscience Approach. ADVANCES IN NEUROBIOLOGY 2024; 39:193-212. [PMID: 39190076 DOI: 10.1007/978-3-031-64839-7_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/28/2024]
Abstract
Astrocytes play an active role in the function of the brain integrating neuronal activity and regulating back neuronal dynamic. They have recently emerged as active contributors of brain's emergent properties such as perceptions. Here, we analyzed the role of astrocytes in pain perception from the lens of systems neuroscience, and we do this by analyzing how astrocytes encode nociceptive information within brain processing areas and how they are key regulators of the internal state that determines pain perception. Specifically, we discuss the dynamic interactions between astrocytes and neuromodulators, such as noradrenaline, highlighting their role in shaping the level of activation of the neuronal ensemble, thereby influencing the experience of pain. Also, we will discuss the possible implications of an "Astro-NeuroMatrix" in the integration of pain across sensory, affective, and cognitive dimensions of pain perception.
Collapse
Affiliation(s)
- Angélica Rivera-Villaseñor
- Escuela Nacional de Estudios Superiores, Universidad Nacional Autónoma de México, Queretaro, Qro., Mexico
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Queretaro, Qro., Mexico
| | - Frida Higinio-Rodríguez
- Escuela Nacional de Estudios Superiores, Universidad Nacional Autónoma de México, Queretaro, Qro., Mexico
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Queretaro, Qro., Mexico
| | - Mónica López-Hidalgo
- Escuela Nacional de Estudios Superiores, Universidad Nacional Autónoma de México, Queretaro, Qro., Mexico.
| |
Collapse
|
14
|
Ohno M. A Strategy for Allowing Earlier Diagnosis and Rigorous Evaluation of BACE1 Inhibitors in Preclinical Alzheimer's Disease. J Alzheimers Dis 2024; 99:431-445. [PMID: 38701146 DOI: 10.3233/jad-231451] [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] [Indexed: 05/05/2024]
Abstract
Given continued failure of BACE1 inhibitor programs at symptomatic and prodromal stages of Alzheimer's disease (AD), clinical trials need to target the earlier preclinical stage. However, trial design is complex in this population with negative diagnosis of classical hippocampal amnesia on standard memory tests. Besides recent advances in brain imaging, electroencephalogram, and fluid-based biomarkers, new cognitive markers should be established for earlier diagnosis that can optimize recruitment to BACE1 inhibitor trials in presymptomatic AD. Notably, accelerated long-term forgetting (ALF) is emerging as a sensitive cognitive measure that can discriminate between asymptomatic individuals with high risks for developing AD and healthy controls. ALF is a form of declarative memory impairment characterized by increased forgetting rates over longer delays (days to months) despite normal storage within the standard delays of testing (20-60 min). Therefore, ALF may represent a harbinger of preclinical dementia and the impairment of systems memory consolidation, during which memory traces temporarily stored in the hippocampus become gradually integrated into cortical networks. This review provides an overview of the utility of ALF in a rational design of next-generation BACE1 inhibitor trials in preclinical AD. I explore potential mechanisms underlying ALF and relevant early-stage biomarkers useful for BACE1 inhibitor evaluation, including synaptic protein alterations, astrocytic dysregulation and neuron hyperactivity in the hippocampal-cortical network. Furthermore, given the physiological role of the isoform BACE2 as an AD-suppressor gene, I also discuss the possible association between the poor selectivity of BACE1 inhibitors and their side effects (e.g., cognitive worsening) in prior clinical trials.
Collapse
Affiliation(s)
- Masuo Ohno
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY, USA
| |
Collapse
|
15
|
Lavekar SS, Patel MD, Montalvo-Parra MD, Krencik R. Asteroid impact: the potential of astrocytes to modulate human neural networks within organoids. Front Neurosci 2023; 17:1305921. [PMID: 38075269 PMCID: PMC10702564 DOI: 10.3389/fnins.2023.1305921] [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: 10/02/2023] [Accepted: 11/08/2023] [Indexed: 02/12/2024] Open
Abstract
Astrocytes are a vital cellular component of the central nervous system that impact neuronal function in both healthy and pathological states. This includes intercellular signals to neurons and non-neuronal cells during development, maturation, and aging that can modulate neural network formation, plasticity, and maintenance. Recently, human pluripotent stem cell-derived neural aggregate cultures, known as neurospheres or organoids, have emerged as improved experimental platforms for basic and pre-clinical neuroscience compared to traditional approaches. Here, we summarize the potential capability of using organoids to further understand the mechanistic role of astrocytes upon neural networks, including the production of extracellular matrix components and reactive signaling cues. Additionally, we discuss the application of organoid models to investigate the astrocyte-dependent aspects of neuropathological diseases and to test astrocyte-inspired technologies. We examine the shortcomings of organoid-based experimental platforms and plausible improvements made possible by cutting-edge neuroengineering technologies. These advancements are expected to enable the development of improved diagnostic strategies and high-throughput translational applications regarding neuroregeneration.
Collapse
Affiliation(s)
| | | | | | - R. Krencik
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX, United States
| |
Collapse
|
16
|
Sanicola HW, Stewart CE, Luther P, Yabut K, Guthikonda B, Jordan JD, Alexander JS. Pathophysiology, Management, and Therapeutics in Subarachnoid Hemorrhage and Delayed Cerebral Ischemia: An Overview. PATHOPHYSIOLOGY 2023; 30:420-442. [PMID: 37755398 PMCID: PMC10536590 DOI: 10.3390/pathophysiology30030032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 08/21/2023] [Accepted: 09/07/2023] [Indexed: 09/28/2023] Open
Abstract
Subarachnoid hemorrhage (SAH) is a type of hemorrhagic stroke resulting from the rupture of an arterial vessel within the brain. Unlike other stroke types, SAH affects both young adults (mid-40s) and the geriatric population. Patients with SAH often experience significant neurological deficits, leading to a substantial societal burden in terms of lost potential years of life. This review provides a comprehensive overview of SAH, examining its development across different stages (early, intermediate, and late) and highlighting the pathophysiological and pathohistological processes specific to each phase. The clinical management of SAH is also explored, focusing on tailored treatments and interventions to address the unique pathological changes that occur during each stage. Additionally, the paper reviews current treatment modalities and pharmacological interventions based on the evolving guidelines provided by the American Heart Association (AHA). Recent advances in our understanding of SAH will facilitate clinicians' improved management of SAH to reduce the incidence of delayed cerebral ischemia in patients.
Collapse
Affiliation(s)
- Henry W. Sanicola
- Department of Neurology, Louisiana State University Health Sciences Center in Shreveport, Shreveport, LA 71103, USA;
| | - Caleb E. Stewart
- Department of Neurosurgery, Louisiana State University Health Sciences Center in Shreveport, Shreveport, LA 71103, USA;
| | - Patrick Luther
- School of Medicine, Louisiana State University Health Sciences Center in Shreveport, Shreveport, LA 71103, USA; (P.L.); (K.Y.)
| | - Kevin Yabut
- School of Medicine, Louisiana State University Health Sciences Center in Shreveport, Shreveport, LA 71103, USA; (P.L.); (K.Y.)
| | - Bharat Guthikonda
- Department of Neurosurgery, Louisiana State University Health Sciences Center in Shreveport, Shreveport, LA 71103, USA;
| | - J. Dedrick Jordan
- Department of Neurology, Louisiana State University Health Sciences Center in Shreveport, Shreveport, LA 71103, USA;
| | - J. Steven Alexander
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center in Shreveport, Shreveport, LA 71103, USA
| |
Collapse
|
17
|
Li H, Guo A, Salgado M, Sáez JC, Lau CG. The connexin hemichannel inhibitor D4 produces rapid antidepressant-like effects in mice. J Neuroinflammation 2023; 20:191. [PMID: 37599352 PMCID: PMC10440914 DOI: 10.1186/s12974-023-02873-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 08/14/2023] [Indexed: 08/22/2023] Open
Abstract
Depression is a common mood disorder characterized by a range of clinical symptoms, including prolonged low mood and diminished interest. Although many clinical and animal studies have provided significant insights into the pathophysiology of depression, current treatment strategies are not sufficient to manage this disorder. It has been suggested that connexin (Cx)-based hemichannels are candidates for depression intervention by modifying the state of neuroinflammation. In this study, we investigated the antidepressant-like effect of a recently discovered selective Cx hemichannel inhibitor, a small organic molecule called D4. We first showed that D4 reduced hemichannel activity following systemic inflammation after LPS injections. Next, we found that D4 treatment prevented LPS-induced inflammatory response and depressive-like behaviors. These behavioral effects were accompanied by reduced astrocytic activation and hemichannel activity in depressive-like mice induced by repeated low-dose LPS challenges. D4 treatment also reverses depressive-like symptoms in mice subjected to chronic restraint stress (CRS). To test whether D4 broadly affected neural activity, we measured c-Fos expression in depression-related brain regions and found a reduction in c-Fos+ cells in different brain regions. D4 significantly normalized CRS-induced hypoactivation in several brain regions, including the hippocampus, entorhinal cortex, and lateral septum. Together, these results indicate that blocking Cx hemichannels using D4 can normalize neuronal activity and reduce depressive-like symptoms in mice by reducing neuroinflammation. Our work provides evidence of the antidepressant-like effect of D4 and supports glial Cx hemichannels as potential therapeutic targets for depression.
Collapse
Affiliation(s)
- Huanhuan Li
- Department of Neuroscience, City University of Hong Kong, Hong Kong SAR, China
- Shenzhen Research Institute, City University of Hong Kong, Shenzhen, China
| | - Anni Guo
- Department of Neuroscience, City University of Hong Kong, Hong Kong SAR, China
- Shenzhen Research Institute, City University of Hong Kong, Shenzhen, China
| | - Magdiel Salgado
- Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, 2381850, Valparaíso, Chile
| | - Juan C Sáez
- Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, 2381850, Valparaíso, Chile
| | - Chunyue Geoffrey Lau
- Department of Neuroscience, City University of Hong Kong, Hong Kong SAR, China.
- Shenzhen Research Institute, City University of Hong Kong, Shenzhen, China.
| |
Collapse
|
18
|
Nuñez A, Zegarra-Valdivia J, Fernandez de Sevilla D, Pignatelli J, Torres Aleman I. The neurobiology of insulin-like growth factor I: From neuroprotection to modulation of brain states. Mol Psychiatry 2023; 28:3220-3230. [PMID: 37353586 DOI: 10.1038/s41380-023-02136-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 05/30/2023] [Accepted: 06/13/2023] [Indexed: 06/25/2023]
Abstract
After decades of research in the neurobiology of IGF-I, its role as a prototypical neurotrophic factor is undisputed. However, many of its actions in the adult brain indicate that this growth factor is not only involved in brain development or in the response to injury. Following a three-layer assessment of its role in the central nervous system, we consider that at the cellular level, IGF-I is indeed a bona fide neurotrophic factor, modulating along ontogeny the generation and function of all the major types of brain cells, contributing to sculpt brain architecture and adaptive responses to damage. At the circuit level, IGF-I modulates neuronal excitability and synaptic plasticity at multiple sites, whereas at the system level, IGF-I intervenes in energy allocation, proteostasis, circadian cycles, mood, and cognition. Local and peripheral sources of brain IGF-I input contribute to a spatially restricted, compartmentalized, and timed modulation of brain activity. To better define these variety of actions, we consider IGF-I a modulator of brain states. This definition aims to reconcile all aspects of IGF-I neurobiology, and may provide a new conceptual framework in the design of future research on the actions of this multitasking neuromodulator in the brain.
Collapse
Affiliation(s)
- A Nuñez
- Department of Anatomy, Histology and Neurosciences, Universidad Autónoma de Madrid, Madrid, Spain
| | - J Zegarra-Valdivia
- Achucarro Basque Center for Neuroscience, Leioa, Spain
- CIBERNED, Madrid, Spain
- Universidad Señor de Sipán, Chiclayo, Perú
| | - D Fernandez de Sevilla
- Department of Anatomy, Histology and Neurosciences, Universidad Autónoma de Madrid, Madrid, Spain
| | - J Pignatelli
- CIBERNED, Madrid, Spain
- Cajal Institute (CSIC), Madrid, Spain
| | - I Torres Aleman
- Achucarro Basque Center for Neuroscience, Leioa, Spain.
- CIBERNED, Madrid, Spain.
- Ikerbasque Science Foundation, Bilbao, Spain.
| |
Collapse
|
19
|
Stogsdill JA, Harwell CC, Goldman SA. Astrocytes as master modulators of neural networks: Synaptic functions and disease-associated dysfunction of astrocytes. Ann N Y Acad Sci 2023; 1525:41-60. [PMID: 37219367 DOI: 10.1111/nyas.15004] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Astrocytes are the most abundant glial cell type in the central nervous system and are essential to the development, plasticity, and maintenance of neural circuits. Astrocytes are heterogeneous, with their diversity rooted in developmental programs modulated by the local brain environment. Astrocytes play integral roles in regulating and coordinating neural activity extending far beyond their metabolic support of neurons and other brain cell phenotypes. Both gray and white matter astrocytes occupy critical functional niches capable of modulating brain physiology on time scales slower than synaptic activity but faster than those adaptive responses requiring a structural change or adaptive myelination. Given their many associations and functional roles, it is not surprising that astrocytic dysfunction has been causally implicated in a broad set of neurodegenerative and neuropsychiatric disorders. In this review, we focus on recent discoveries concerning the contributions of astrocytes to the function of neural networks, with a dual focus on the contribution of astrocytes to synaptic development and maturation, and on their role in supporting myelin integrity, and hence conduction and its regulation. We then address the emerging roles of astrocytic dysfunction in disease pathogenesis and on potential strategies for targeting these cells for therapeutic purposes.
Collapse
Affiliation(s)
| | - Corey C Harwell
- Department of Neurology, University of California San Francisco, San Francisco, California, USA
| | - Steven A Goldman
- Sana Biotechnology Inc., Cambridge, Massachusetts, USA
- Center for Translational Neuromedicine, University of Rochester, Rochester, New York, USA
- University of Copenhagen Faculty of Health and Medical Sciences, Copenhagen, Denmark
| |
Collapse
|
20
|
Tewari BP, Harshad PA, Singh M, Joshi NB, Joshi PG. Pilocarpine-induced acute seizure causes rapid area-specific astrogliosis and alters purinergic signaling in rat hippocampus. Brain Res 2023:148444. [PMID: 37290610 DOI: 10.1016/j.brainres.2023.148444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 05/31/2023] [Accepted: 06/02/2023] [Indexed: 06/10/2023]
Abstract
The progressive nature of acquired epilepsy warrants a thorough examination of acute changes that occur immediately after an epileptogenic insult to better understand the cellular and molecular mechanisms that trigger epileptogenesis. Astrocytes are important regulators of neuronal functions and emerging evidence suggests an involvement of astrocytic purinergic signaling in the etiology of acquired epilepsies. However, how astrocytic purinergic signaling responds immediately after an acute seizure or an epileptogenic insult to impact epileptogenesis is not well studied. In the present study, we report area-specific rapid onset of astrocytic changes in morphology, as well as in expression and functional activity of the purinergic signaling in the hippocampus that occur immediately after pilocarpine-induced stage 5 seizure. After 3 hours of stage 5 acute seizure, hippocampal astrocytes show increased intrinsic calcium activity in stratum radiatum as well as reactive astrogliosis in the stratum lacunosum moleculare and hilus regions of the hippocampus. Hilar astrocytes also upregulated the expression of P2Y1 and P2Y2 metabotropic purinergic receptors. Subsequently, P2Y1 exhibited a functional upregulation by showing a significantly higher intracellular calcium rise in ex-vivo hippocampal slices on P2Y1 activation. Our results suggest that hippocampal astrocytes undergo rapid area-specific morphological and functional changes immediately after the commencement of the seizure activity and purinergic receptors upregulation is one of the earliest changes in response to seizure activity. These changes can be considered acute astrocytic responses to seizure activity which can potentially drive the epileptogenesis and can be explored further to identify astrocyte-specific targets for seizure therapy.
Collapse
Affiliation(s)
- Bhanu P Tewari
- Department of Biophysics, National Institute of mental health and Neuroscience (NIMHANS), Hosur Road, Bangalore, 560029, Karnataka, India.
| | - P A Harshad
- Department of Biophysics, National Institute of mental health and Neuroscience (NIMHANS), Hosur Road, Bangalore, 560029, Karnataka, India
| | - Mahendra Singh
- Department of Biophysics, National Institute of mental health and Neuroscience (NIMHANS), Hosur Road, Bangalore, 560029, Karnataka, India
| | - Nanda B Joshi
- Department of Biophysics, National Institute of mental health and Neuroscience (NIMHANS), Hosur Road, Bangalore, 560029, Karnataka, India
| | - Preeti G Joshi
- Department of Biophysics, National Institute of mental health and Neuroscience (NIMHANS), Hosur Road, Bangalore, 560029, Karnataka, India.
| |
Collapse
|
21
|
Andrade-Talavera Y, Fisahn A, Rodríguez-Moreno A. Timing to be precise? An overview of spike timing-dependent plasticity, brain rhythmicity, and glial cells interplay within neuronal circuits. Mol Psychiatry 2023; 28:2177-2188. [PMID: 36991134 PMCID: PMC10611582 DOI: 10.1038/s41380-023-02027-w] [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: 08/03/2022] [Revised: 02/27/2023] [Accepted: 03/01/2023] [Indexed: 03/31/2023]
Abstract
In the mammalian brain information processing and storage rely on the complex coding and decoding events performed by neuronal networks. These actions are based on the computational ability of neurons and their functional engagement in neuronal assemblies where precise timing of action potential firing is crucial. Neuronal circuits manage a myriad of spatially and temporally overlapping inputs to compute specific outputs that are proposed to underly memory traces formation, sensory perception, and cognitive behaviors. Spike-timing-dependent plasticity (STDP) and electrical brain rhythms are suggested to underlie such functions while the physiological evidence of assembly structures and mechanisms driving both processes continues to be scarce. Here, we review foundational and current evidence on timing precision and cooperative neuronal electrical activity driving STDP and brain rhythms, their interactions, and the emerging role of glial cells in such processes. We also provide an overview of their cognitive correlates and discuss current limitations and controversies, future perspectives on experimental approaches, and their application in humans.
Collapse
Affiliation(s)
- Yuniesky Andrade-Talavera
- Laboratory of Cellular Neuroscience and Plasticity, Department of Physiology, Anatomy and Cell Biology, Universidad Pablo de Olavide, ES-41013, Seville, Spain.
| | - André Fisahn
- Department of Biosciences and Nutrition and Department of Women's and Children's Health, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Antonio Rodríguez-Moreno
- Laboratory of Cellular Neuroscience and Plasticity, Department of Physiology, Anatomy and Cell Biology, Universidad Pablo de Olavide, ES-41013, Seville, Spain.
| |
Collapse
|
22
|
Madeira D, Lopes CR, Simões AP, Canas PM, Cunha RA, Agostinho P. Astrocytic A 2A receptors silencing negatively impacts hippocampal synaptic plasticity and memory of adult mice. Glia 2023. [PMID: 37183905 DOI: 10.1002/glia.24384] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 04/28/2023] [Accepted: 05/02/2023] [Indexed: 05/16/2023]
Abstract
Astrocytes are wired to bidirectionally communicate with neurons namely with synapses, thus shaping synaptic plasticity, which in the hippocampus is considered to underlie learning and memory. Adenosine A2A receptors (A2A R) are a potential candidate to modulate this bidirectional communication, since A2A R regulate synaptic plasticity and memory and also control key astrocytic functions. Nonetheless, little is known about the role of astrocytic A2A R in synaptic plasticity and hippocampal-dependent memory. Here, we investigated the impact of genetic silencing astrocytic A2A R on hippocampal synaptic plasticity and memory of adult mice. The genetic A2A R silencing in astrocytes was accomplished by a bilateral injection into the CA1 hippocampal area of a viral construct (AAV5-GFAP-GFP-Cre) that inactivate A2A R expression in astrocytes of male adult mice carrying "floxed" A2A R gene, as confirmed by A2A R binding assays. Astrocytic A2A R silencing alters astrocytic morphology, typified by an increment of astrocytic arbor complexity, and led to deficits in spatial reference memory and compromised hippocampal synaptic plasticity, typified by a reduction of LTP magnitude and a shift of synaptic long-term depression (LTD) toward LTP. These data indicate that astrocytic A2A R control astrocytic morphology and influence hippocampal synaptic plasticity and memory of adult mice in a manner different from neuronal A2A R.
Collapse
Affiliation(s)
- Daniela Madeira
- Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal
- Center for Neuroscience and Cell Biology- University of Coimbra (CNC- UC), Coimbra, Portugal
| | - Cátia R Lopes
- Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal
- Center for Neuroscience and Cell Biology- University of Coimbra (CNC- UC), Coimbra, Portugal
| | - Ana P Simões
- Center for Neuroscience and Cell Biology- University of Coimbra (CNC- UC), Coimbra, Portugal
| | - Paula M Canas
- Center for Neuroscience and Cell Biology- University of Coimbra (CNC- UC), Coimbra, Portugal
| | - Rodrigo A Cunha
- Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal
- Center for Neuroscience and Cell Biology- University of Coimbra (CNC- UC), Coimbra, Portugal
| | - Paula Agostinho
- Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal
- Center for Neuroscience and Cell Biology- University of Coimbra (CNC- UC), Coimbra, Portugal
| |
Collapse
|
23
|
Stasenko SV, Kazantsev VB. Information Encoding in Bursting Spiking Neural Network Modulated by Astrocytes. ENTROPY (BASEL, SWITZERLAND) 2023; 25:e25050745. [PMID: 37238500 DOI: 10.3390/e25050745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/28/2023] [Accepted: 04/28/2023] [Indexed: 05/28/2023]
Abstract
We investigated a mathematical model composed of a spiking neural network (SNN) interacting with astrocytes. We analysed how information content in the form of two-dimensional images can be represented by an SNN in the form of a spatiotemporal spiking pattern. The SNN includes excitatory and inhibitory neurons in some proportion, sustaining the excitation-inhibition balance of autonomous firing. The astrocytes accompanying each excitatory synapse provide a slow modulation of synaptic transmission strength. An information image was uploaded to the network in the form of excitatory stimulation pulses distributed in time reproducing the shape of the image. We found that astrocytic modulation prevented stimulation-induced SNN hyperexcitation and non-periodic bursting activity. Such homeostatic astrocytic regulation of neuronal activity makes it possible to restore the image supplied during stimulation and lost in the raster diagram of neuronal activity due to non-periodic neuronal firing. At a biological point, our model shows that astrocytes can act as an additional adaptive mechanism for regulating neural activity, which is crucial for sensory cortical representations.
Collapse
Affiliation(s)
- Sergey V Stasenko
- Laboratory of Advanced Methods for High-Dimensional Data Analysis, Lobachevsky State University of Nizhny Novgorod, 603022 Nizhny Novgorod, Russia
| | - Victor B Kazantsev
- Laboratory of Advanced Methods for High-Dimensional Data Analysis, Lobachevsky State University of Nizhny Novgorod, 603022 Nizhny Novgorod, Russia
| |
Collapse
|
24
|
Golf SR, Trotter JH, Nakahara G, Südhof TC. Astrocytic Neuroligins Are Not Required for Synapse Formation or a Normal Astrocyte Cytoarchitecture. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.10.536254. [PMID: 37090508 PMCID: PMC10120619 DOI: 10.1101/2023.04.10.536254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Astrocytes exert multifarious roles in the formation, regulation, and function of synapses in the brain, but the mechanisms involved remain unclear. Interestingly, astrocytes abundantly express neuroligins, postsynaptic adhesion molecules that bind to presynaptic neurexins. A pioneering recent study reported that loss-of-function of neuroligins in astrocytes impairs excitatory synapse formation and astrocyte morphogenesis. This study suggested a crucial synaptic function for astrocytic neuroligins but was puzzling given that constitutive neuroligin deletions do not decrease excitatory synapse numbers. Thus, we here examined the function of astrocytic neuroligins using a rigorous conditional genetic approach with deletion of all major neuroligins (Nlgn1-3) in astrocytes. Our results show that early postnatal deletion of neuroligins from astrocytes has no effect on cortical or hippocampal synapses and does not alter the cytoarchitecture of astrocytes. Thus, astrocytic neuroligins are unlikely to shape synapse formation or astrocyte development but may perform other important functions in astrocytes.
Collapse
Affiliation(s)
- Samantha R. Golf
- Dept. of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Justin H. Trotter
- Dept. of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - George Nakahara
- Dept. of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Thomas C. Südhof
- Dept. of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| |
Collapse
|
25
|
Terradillos I, Bonilla-Del Río I, Puente N, Serrano M, Mimenza A, Lekunberri L, Anaut-Lusar I, Reguero L, Gerrikagoitia I, Ruiz de Martín Esteban S, Hillard CJ, Grande MT, Romero J, Elezgarai I, Grandes P. Altered glial expression of the cannabinoid 1 receptor in the subiculum of a mouse model of Alzheimer's disease. Glia 2023; 71:866-879. [PMID: 36437738 DOI: 10.1002/glia.24312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 10/23/2022] [Accepted: 11/18/2022] [Indexed: 11/29/2022]
Abstract
The alteration of the endocannabinoid tone usually associates with changes in the expression and/or function of the cannabinoid CB1 receptor. In Alzheimer's disease (AD), amyloid beta (Aβ)-containing aggregates induce a chronic inflammatory response leading to reactivity of both microglia and astrocytes. However, how this glial response impacts on the glial CB1 receptor expression in the subiculum of a mouse model of AD, a brain region particularly affected by large accumulation of plaques and concomitant subcellular changes in microglia and astrocytes, is unknown. The CB1 receptor localization in both glial cells was investigated in the subiculum of male 5xFAD/CB2 EGFP/f/f (AD model) and CB2 EGFP/f/f mice by immuno-electron microscopy. The findings revealed that glial CB1 receptors suffer remarkable changes in the AD mouse. Thus, CB1 receptor expression increases in reactive microglia in 5xFAD/CB2 EGFP/f/f , but remains constant in astrocytes with CB1 receptor labeling rising proportionally to the perimeter of the reactive astrocytes. Not least, the CB1 receptor localization in microglial processes in the subiculum of controls and closely surrounding amyloid plaques and dystrophic neurites of the AD model, supports previous suggestions of the presence of the CB1 receptor in microglia. These findings on the correlation between glial reactivity and the CB1 receptor expression in microglial cells and astrocytes, contribute to the understanding of the role of the endocannabinoid system in the pathophysiology of Alzheimer's disease.
Collapse
Affiliation(s)
- Itziar Terradillos
- Department of Neurosciences, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain.,Achucarro Basque Center for Neuroscience, Leioa, Spain
| | - Itziar Bonilla-Del Río
- Department of Neurosciences, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain.,Achucarro Basque Center for Neuroscience, Leioa, Spain
| | - Nagore Puente
- Department of Neurosciences, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain.,Achucarro Basque Center for Neuroscience, Leioa, Spain
| | - Maitane Serrano
- Department of Neurosciences, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain.,Achucarro Basque Center for Neuroscience, Leioa, Spain
| | - Amaia Mimenza
- Department of Neurosciences, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain.,Achucarro Basque Center for Neuroscience, Leioa, Spain
| | - Leire Lekunberri
- Department of Neurosciences, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain.,Achucarro Basque Center for Neuroscience, Leioa, Spain
| | - Ilazki Anaut-Lusar
- Department of Neurosciences, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain.,Achucarro Basque Center for Neuroscience, Leioa, Spain
| | - Leire Reguero
- Department of Neurosciences, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain.,Achucarro Basque Center for Neuroscience, Leioa, Spain
| | - Inmaculada Gerrikagoitia
- Department of Neurosciences, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain.,Achucarro Basque Center for Neuroscience, Leioa, Spain
| | | | - Cecilia J Hillard
- Department of Pharmacology and Toxicology, Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - María T Grande
- Faculty of Experimental Sciences, Universidad Francisco de Vitoria, Pozuelo de Alarcón, Spain
| | - Julián Romero
- Faculty of Experimental Sciences, Universidad Francisco de Vitoria, Pozuelo de Alarcón, Spain
| | - Izaskun Elezgarai
- Department of Neurosciences, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain.,Achucarro Basque Center for Neuroscience, Leioa, Spain
| | - Pedro Grandes
- Department of Neurosciences, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain.,Achucarro Basque Center for Neuroscience, Leioa, Spain
| |
Collapse
|
26
|
Hess EM, Kassel SN, Simandl G, Raddatz N, Maunze B, Hurley MM, Grzybowski M, Klotz J, Geurts A, Liu QS, Choi S, Twining RC, Baker DA. Genetic Disruption of System xc-Mediated Glutamate Release from Astrocytes Increases Negative-Outcome Behaviors While Preserving Basic Brain Function in Rat. J Neurosci 2023; 43:2349-2361. [PMID: 36788029 PMCID: PMC10072291 DOI: 10.1523/jneurosci.1525-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 01/04/2023] [Accepted: 02/02/2023] [Indexed: 02/16/2023] Open
Abstract
The importance of neuronal glutamate to synaptic transmission throughout the brain illustrates the immense therapeutic potential and safety risks of targeting this system. Astrocytes also release glutamate, the clinical relevance of which is unknown as the range of brain functions reliant on signaling from these cells hasn't been fully established. Here, we investigated system xc- (Sxc), which is a glutamate release mechanism with an in vivo rodent expression pattern that is restricted to astrocytes. As most animals do not express Sxc, we first compared the expression and sequence of the obligatory Sxc subunit xCT among major classes of vertebrate species. We found xCT to be ubiquitously expressed and under significant negative selective pressure. Hence, Sxc likely confers important advantages to vertebrate brain function that may promote biological fitness. Next, we assessed brain function in male genetically modified rats (MSxc) created to eliminate Sxc activity. Unlike other glutamatergic mechanisms, eliminating Sxc activity was not lethal and didn't alter growth patterns, telemetry measures of basic health, locomotor activity, or behaviors reliant on simple learning. However, MSxc rats exhibited deficits in tasks used to assess cognitive behavioral control. In a pavlovian conditioned approach, MSxc rats approached a food-predicted cue more frequently than WT rats, even when this response was punished. In attentional set shifting, MSxc rats displayed cognitive inflexibility because of an increased frequency of perseverative errors. MSxc rats also displayed heightened cocaine-primed drug seeking. Hence, a loss of Sxc-activity appears to weaken control over nonreinforced or negative-outcome behaviors without altering basic brain function.SIGNIFICANCE STATEMENT Glutamate is essential to synaptic activity throughout the brain, which illustrates immense therapeutic potential and risk. Notably, glutamatergic mechanisms are expressed by most types of brain cells. Hence, glutamate likely encodes multiple forms of intercellular signaling. Here, we hypothesized that the selective manipulation of astrocyte to neuron signaling would alter cognition without producing widespread brain impairments. First, we eliminated activity of the astrocytic glutamate release mechanism, Sxc, in rat. This impaired cognitive flexibility and increased expression of perseverative, maladaptive behaviors. Notably, eliminating Sxc activity did not alter metrics of health or noncognitive brain function. These data add to recent evidence that the brain expresses cognition-specific molecular mechanisms that could lead to highly precise, safe medications for impaired cognition.
Collapse
Affiliation(s)
- Evan M Hess
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53233
| | - Sara N Kassel
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53233
| | - Gregory Simandl
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53233
| | - Nicholas Raddatz
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53233
| | - Brian Maunze
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53233
| | - Matthew M Hurley
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53233
| | | | | | | | - Qing-Song Liu
- Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - SuJean Choi
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53233
| | - Robert C Twining
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53233
| | - David A Baker
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53233
| |
Collapse
|
27
|
Astrocyte strategies in the energy-efficient brain. Essays Biochem 2023; 67:3-16. [PMID: 36350053 DOI: 10.1042/ebc20220077] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 10/11/2022] [Accepted: 10/13/2022] [Indexed: 11/10/2022]
Abstract
Astrocytes generate ATP through glycolysis and mitochondrion respiration, using glucose, lactate, fatty acids, amino acids, and ketone bodies as metabolic fuels. Astrocytic mitochondria also participate in neuronal redox homeostasis and neurotransmitter recycling. In this essay, we aim to integrate the multifaceted evidence about astrocyte bioenergetics at the cellular and systems levels, with a focus on mitochondrial oxidation. At the cellular level, the use of fatty acid β-oxidation and the existence of molecular switches for the selection of metabolic mode and fuels are examined. At the systems level, we discuss energy audits of astrocytes and how astrocytic Ca2+ signaling might contribute to the higher performance and lower energy consumption of the brain as compared to engineered circuits. We finish by examining the neural-circuit dysregulation and behavior impairment associated with alterations of astrocytic mitochondria. We conclude that astrocytes may contribute to brain energy efficiency by coupling energy, redox, and computational homeostasis in neural circuits.
Collapse
|
28
|
Mitochondrial Ca2+ handling as a cell signaling hub: lessons from astrocyte function. Essays Biochem 2023; 67:63-75. [PMID: 36636961 DOI: 10.1042/ebc20220094] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 12/16/2022] [Accepted: 12/22/2022] [Indexed: 01/14/2023]
Abstract
Astrocytes are a heterogenous population of macroglial cells spread throughout the central nervous system with diverse functions, expression signatures, and intricate morphologies. Their subcellular compartments contain a distinct range of mitochondria, with functional microdomains exhibiting widespread activities, such as controlling local metabolism and Ca2+ signaling. Ca2+ is an ion of utmost importance, both physiologically and pathologically, and participates in critical central nervous system processes, including synaptic plasticity, neuron-astrocyte integration, excitotoxicity, and mitochondrial physiology and metabolism. The mitochondrial Ca2+ handling system is formed by the mitochondrial Ca2+ uniporter complex (MCUc), which mediates Ca2+ influx, and the mitochondrial Na+/Ca2+ exchanger (NCLX), responsible for most mitochondrial Ca2+ efflux, as well as additional components, including the mitochondrial permeability transition pore (mtPTP). Over the last decades, mitochondrial Ca2+ handling has been shown to be key for brain homeostasis, acting centrally in physiopathological processes such as astrogliosis, astrocyte-neuron activity integration, energy metabolism control, and neurodegeneration. In this review, we discuss the current state of knowledge regarding the mitochondrial Ca2+ handling system molecular composition, highlighting its impact on astrocytic homeostasis.
Collapse
|
29
|
Astroglial CB1 receptors, energy metabolism, and gliotransmission: an integrated signaling system? Essays Biochem 2023; 67:49-61. [PMID: 36645029 DOI: 10.1042/ebc20220089] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 12/06/2022] [Accepted: 12/07/2022] [Indexed: 01/17/2023]
Abstract
Astrocytes are key players in brain homeostasis and function. During the last years, several studies have cemented this notion by showing that these cells respond to neuronal signals and, via the release of molecules that modulate and support synaptic activity (gliotransmission) participates in the functions of the so-called tripartite synapse. Thus, besides their established control of brain metabolism, astrocytes can also actively control synaptic activity and behavior. Among the signaling pathways that shape the functions of astrocyte, the cannabinoid type-1 (CB1) receptor is emerging as a critical player in the control of both gliotransmission and the metabolic cooperation between astrocytes and neurons. In the present short review, we describe known and newly discovered properties of the astroglial CB1 receptors and their role in modulating brain function and behavior. Based on this evidence, we finally discuss how the functions and mode of actions of astrocyte CB1 receptors might represent a clear example of the inextricable relationship between energy metabolism and gliotransmission. These tight interactions will need to be taken into account for future research in astrocyte functions and call for a reinforcement of the theoretical and experimental bridges between studies on metabolic and synaptic functions of astrocytes.
Collapse
|
30
|
Astrocytes in memory formation and maintenance. Essays Biochem 2023; 67:107-117. [PMID: 36148596 DOI: 10.1042/ebc20220091] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 09/05/2022] [Accepted: 09/06/2022] [Indexed: 11/17/2022]
Abstract
Learning and memory are fundamental but highly complex functions of the brain. They rely on multiple mechanisms including the processing of sensory information, memory formation, maintenance of short- and long-term memory, memory retrieval and memory extinction. Recent experiments provide strong evidence that, besides neurons, astrocytes crucially contribute to these higher brain functions. However, the complex interplay of astrocytes and neurons in local neuron-glia assemblies is far from being understood. Although important basic cellular principles that govern and link neuronal and astrocytic cellular functions have been established, additional mechanisms clearly continue to emerge. In this short essay, we first review current technologies allowing the experimenter to explore the role of astrocytes in behaving animals, with focus on spatial memory. We then discuss astrocytic signaling mechanisms and their role in learning and memory. We also reveal gaps in our knowledge that currently prevent a comprehensive understanding of how astrocytes contribute to acquisition, storage and retrieval of memory by modulating neuronal signaling in local circuits.
Collapse
|
31
|
Marchese NA, Ríos MN, Guido ME. Müller glial cell photosensitivity: a novel function bringing higher complexity to vertebrate retinal physiology. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY 2023. [DOI: 10.1016/j.jpap.2023.100162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
|
32
|
Looking to the stars for answers: Strategies for determining how astrocytes influence neuronal activity. Comput Struct Biotechnol J 2022; 20:4146-4156. [PMID: 36016711 PMCID: PMC9379862 DOI: 10.1016/j.csbj.2022.07.052] [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: 07/07/2022] [Revised: 07/29/2022] [Accepted: 07/29/2022] [Indexed: 11/24/2022] Open
Abstract
Astrocytes are critical components of neural circuits positioned in close proximity to the synapse, allowing them to rapidly sense and respond to neuronal activity. One repeatedly observed biomarker of astroglial activation is an increase in intracellular Ca2+ levels. These astroglial Ca2+ signals are often observed spreading throughout various cellular compartments from perisynaptic astroglial processes, to major astrocytic branches and on to the soma or cell body. Here we review recent evidence demonstrating that astrocytic Ca2+ events are remarkably heterogeneous in both form and function, propagate through the astroglial syncytia, and are directly linked to the ability of astroglia to influence local neuronal activity. As many of the cellular functions of astroglia can be linked to intracellular Ca2+ signaling, and the diversity and heterogeneity of these events becomes more apparent, there is an increasing need for novel experimental strategies designed to better understand the how these signals evolve in parallel with neuronal activity. Here we review the recent advances that enable the characterization of both subcellular and population-wide astrocytic Ca2+ dynamics. Additionally, we also outline the experimental design required for simultaneous in vivo Ca2+ imaging in the context of neuronal or astroglial manipulation, highlighting new experimental strategies made possible by recent advances in viral vector, imaging, and quantification technologies. Through combined usage of these reagents and methodologies, we provide a conceptual framework to study how astrocytes functionally integrate into neural circuits and to what extent they influence and direct the synaptic activity underlying behavioral responses.
Collapse
|