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Pan X, Gao Y, Guan K, Chen J, Ji B. Ghrelin/GHSR System in Depressive Disorder: Pathologic Roles and Therapeutic Implications. Curr Issues Mol Biol 2024; 46:7324-7338. [PMID: 39057075 PMCID: PMC11275499 DOI: 10.3390/cimb46070434] [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: 05/29/2024] [Revised: 07/03/2024] [Accepted: 07/08/2024] [Indexed: 07/28/2024] Open
Abstract
Depression is the most common chronic mental illness and is characterized by low mood, insomnia, and affective disorders. However, its pathologic mechanisms remain unclear. Numerous studies have suggested that the ghrelin/GHSR system may be involved in the pathophysiologic process of depression. Ghrelin plays a dual role in experimental animals, increasing depressed behavior and decreasing anxiety. By combining several neuropeptides and traditional neurotransmitter systems to construct neural networks, this hormone modifies signals connected to depression. The present review focuses on the role of ghrelin in neuritogenesis, astrocyte protection, inflammatory factor production, and endocrine disruption in depression. Furthermore, ghrelin/GHSR can activate multiple signaling pathways, including cAMP/CREB/BDNF, PI3K/Akt, Jak2/STAT3, and p38-MAPK, to produce antidepressant effects, given which it is expected to become a potential therapeutic target for the treatment of depression.
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Affiliation(s)
- Xingli Pan
- School of Biological Sciences, Jining Medical University, Jining 272067, China;
| | - Yuxin Gao
- School of Clinical Medicine, Jining Medical University, Jining 272067, China; (Y.G.); (K.G.)
| | - Kaifu Guan
- School of Clinical Medicine, Jining Medical University, Jining 272067, China; (Y.G.); (K.G.)
| | - Jing Chen
- Neurobiology Institute, Jining Medical University, Jining 272067, China
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK
| | - Bingyuan Ji
- Institute of Precision Medicine, Jining Medical University, Jining 272067, China
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2
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Abbondanza A, Urushadze A, Alves-Barboza AR, Janickova H. Expression and function of nicotinic acetylcholine receptors in specific neuronal populations: Focus on striatal and prefrontal circuits. Pharmacol Res 2024; 204:107190. [PMID: 38704107 DOI: 10.1016/j.phrs.2024.107190] [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: 02/26/2024] [Revised: 04/19/2024] [Accepted: 04/20/2024] [Indexed: 05/06/2024]
Abstract
Nicotinic acetylcholine receptors (nAChRs) are widely expressed in the central nervous system and play an important role in the control of neural functions including neuronal activity, transmitter release and synaptic plasticity. Although the common subtypes of nAChRs are abundantly expressed throughout the brain, their expression in different brain regions and by individual neuronal types is not homogeneous or incidental. In recent years, several studies have emerged showing that particular subtypes of nAChRs are expressed by specific neuronal populations in which they have major influence on the activity of local circuits and behavior. It has been demonstrated that even nAChRs expressed by relatively rare neuronal types can induce significant changes in behavior and contribute to pathological processes. Depending on the identity and connectivity of the particular nAChRs-expressing neuronal populations, the activation of nAChRs can have distinct or even opposing effects on local neuronal signaling. In this review, we will summarize the available literature describing the expression of individual nicotinic subunits by different neuronal types in two crucial brain regions, the striatum and the prefrontal cortex. The review will also briefly discuss nicotinic expression in non-neuronal, glial cells, as they cannot be ignored as potential targets of nAChRs-modulating drugs. The final section will discuss options that could allow us to target nAChRs in a neuronal-type-specific manner, not only in the experimental field, but also eventually in clinical practice.
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Affiliation(s)
- Alice Abbondanza
- Laboratory of Neurochemistry, Institute of Physiology of the Czech Academy of Sciences, Prague 14200, Czech Republic
| | - Anna Urushadze
- Laboratory of Neurochemistry, Institute of Physiology of the Czech Academy of Sciences, Prague 14200, Czech Republic
| | - Amanda Rosanna Alves-Barboza
- Laboratory of Neurochemistry, Institute of Physiology of the Czech Academy of Sciences, Prague 14200, Czech Republic
| | - Helena Janickova
- Laboratory of Neurochemistry, Institute of Physiology of the Czech Academy of Sciences, Prague 14200, Czech Republic.
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3
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Lombardi AM, Wong H, Bower ME, Milstead R, Borski C, Schmitt E, Griffioen M, LaPlante L, Ehringer MA, Stitzel J, Hoeffer CA. AKT2 modulates astrocytic nicotine responses in vivo. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.31.596856. [PMID: 38854016 PMCID: PMC11160815 DOI: 10.1101/2024.05.31.596856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
A better understanding of nicotine neurobiology is needed to reduce or prevent chronic addiction, ameliorate the detrimental effects of nicotine withdrawal, and increase successful cessation of use. Nicotine binds and activates two astrocyte-expressed nicotinic acetylcholine receptors (nAChRs), α4β2 and α7. We recently found that Protein kinase B-β (Pkb-β or Akt2) expression is restricted to astrocytes in mice and humans. To determine if AKT2 plays a role in astrocytic nicotinic responses, we generated astrocyte-specific Akt2 conditional knockout (cKO) and full Akt2 KO mice for in vivo and in vitro experiments. For in vivo studies, we examined mice exposed to chronic nicotine for two weeks in drinking water (200 μg/mL) and following acute nicotine challenge (0.09, 0.2 mg/kg) after 24 hrs. Our in vitro studies used cultured mouse astrocytes to measure nicotine-dependent astrocytic responses. We validated our approaches using lipopolysaccharide (LPS) exposure inducing astrogliosis. Sholl analysis was used to measure glial fibrillary acidic protein responses in astrocytes. Our data show that wild-type (WT) mice exhibit increased astrocyte morphological complexity during acute nicotine exposure, with decreasing complexity during chronic nicotine use, whereas Akt2 cKO mice showed increased astrocyte morphology complexity. In culture, we found that 100μM nicotine was sufficient for morphological changes and blocking α7 or α4β2 nAChRs prevented observed morphologic changes. Finally, we performed conditioned place preference (CPP) in Akt2 cKO mice and found that astrocytic AKT2 deficiency reduced nicotine preference compared to controls. These findings show the importance of nAChRs and Akt2 signaling in the astrocytic response to nicotine.
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Affiliation(s)
- Andrew M. Lombardi
- Department of Integrative Physiology, University of Colorado, Boulder, CO 80303
| | - Helen Wong
- Institute for Behavioral Genetics, University of Colorado, Boulder, CO 80309
| | - Myra E. Bower
- Department of Integrative Physiology, University of Colorado, Boulder, CO 80303
- Institute for Behavioral Genetics, University of Colorado, Boulder, CO 80309
| | - Ryan Milstead
- Department of Integrative Physiology, University of Colorado, Boulder, CO 80303
- Institute for Behavioral Genetics, University of Colorado, Boulder, CO 80309
| | - Curtis Borski
- Institute for Behavioral Genetics, University of Colorado, Boulder, CO 80309
| | - Emily Schmitt
- Department of Integrative Physiology, University of Colorado, Boulder, CO 80303
| | - Mina Griffioen
- Department of Integrative Physiology, University of Colorado, Boulder, CO 80303
- Institute for Behavioral Genetics, University of Colorado, Boulder, CO 80309
| | - Lauren LaPlante
- Institute for Behavioral Genetics, University of Colorado, Boulder, CO 80309
| | - Marissa A. Ehringer
- Department of Integrative Physiology, University of Colorado, Boulder, CO 80303
- Institute for Behavioral Genetics, University of Colorado, Boulder, CO 80309
| | - Jerry Stitzel
- Department of Integrative Physiology, University of Colorado, Boulder, CO 80303
- Institute for Behavioral Genetics, University of Colorado, Boulder, CO 80309
| | - Charles A. Hoeffer
- Department of Integrative Physiology, University of Colorado, Boulder, CO 80303
- Institute for Behavioral Genetics, University of Colorado, Boulder, CO 80309
- Linda Crnic Institute, Anschutz Medical Center, Aurora, CO 80045
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4
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Syvänen V, Koistinaho J, Lehtonen Š. Identification of the abnormalities in astrocytic functions as potential drug targets for neurodegenerative disease. Expert Opin Drug Discov 2024; 19:603-616. [PMID: 38409817 DOI: 10.1080/17460441.2024.2322988] [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: 10/26/2023] [Accepted: 02/21/2024] [Indexed: 02/28/2024]
Abstract
INTRODUCTION Historically, astrocytes were seen primarily as a supportive cell population within the brain; with neurodegenerative disease research focusing exclusively on malfunctioning neurons. However, astrocytes perform numerous tasks that are essential for maintenance of the central nervous system`s complex processes. Disruption of these functions can have negative consequences; hence, it is unsurprising to observe a growing amount of evidence for the essential role of astrocytes in the development and progression of neurodegenerative diseases. Targeting astrocytic functions may serve as a potential disease-modifying drug therapy in the future. AREAS COVERED The present review emphasizes the key astrocytic functions associated with neurodegenerative diseases and explores the possibility of pharmaceutical interventions to modify these processes. In addition, the authors provide an overview of current advancement in this field by including studies of possible drug candidates. EXPERT OPINION Glial research has experienced a significant renaissance in the last quarter-century. Understanding how disease pathologies modify or are caused by astrocyte functions is crucial when developing treatments for brain diseases. Future research will focus on building advanced models that can more precisely correlate to the state in the human brain, with the goal of routinely testing therapies in these models.
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Affiliation(s)
- Valtteri Syvänen
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Jari Koistinaho
- Neuroscience Center, Helsinki Institute of Life Science, and Drug Research Program, Division of Pharmacology and Pharmacotherapy, University of Helsinki, Helsinki, Finland
| | - Šárka Lehtonen
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
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5
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Evans WR, Baskar SS, Costa ARCE, Ravoori S, Arigbe A, Huda R. Functional activation of dorsal striatum astrocytes improves movement deficits in hemi-parkinsonian mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.02.587694. [PMID: 38617230 PMCID: PMC11014576 DOI: 10.1101/2024.04.02.587694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Parkinson's disease (PD) is characterized by the degeneration of dopaminergic nigrostriatal inputs, which causes striatal network dysfunction and leads to pronounced motor deficits. Recent evidence highlights astrocytes as a potential local source of striatal network modulation. However, it remains unknown how dopamine loss affects striatal astrocyte activity and whether astrocyte activity regulates behavioral deficits in PD. We addressed these questions by performing astrocyte-specific calcium recordings and manipulations using in vivo fiber photometry and chemogenetics. We find that locomotion elicits astrocyte calcium activity over a slower timescale than neurons. Unilateral dopamine depletion reduced locomotion-related astrocyte responses. Chemogenetic activation facilitated astrocyte activity, and improved asymmetrical motor deficits and open field exploratory behavior in dopamine lesioned mice. Together, our results establish a novel role for functional striatal astrocyte signaling in modulating motor function in PD and highlight non-neuronal targets for potential PD therapeutics.
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Affiliation(s)
- Wesley R. Evans
- WM Keck Center for Collaborative Neuroscience, Rutgers University, Piscataway NJ, 08854, USA
| | - Sindhuja S. Baskar
- WM Keck Center for Collaborative Neuroscience, Rutgers University, Piscataway NJ, 08854, USA
| | | | - Sanya Ravoori
- WM Keck Center for Collaborative Neuroscience, Rutgers University, Piscataway NJ, 08854, USA
| | - Abimbola Arigbe
- WM Keck Center for Collaborative Neuroscience, Rutgers University, Piscataway NJ, 08854, USA
| | - Rafiq Huda
- WM Keck Center for Collaborative Neuroscience, Rutgers University, Piscataway NJ, 08854, USA
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway NJ, 08854, USA
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6
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Escalada P, Ezkurdia A, Ramírez MJ, Solas M. Essential Role of Astrocytes in Learning and Memory. Int J Mol Sci 2024; 25:1899. [PMID: 38339177 PMCID: PMC10856373 DOI: 10.3390/ijms25031899] [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: 01/17/2024] [Revised: 01/31/2024] [Accepted: 02/02/2024] [Indexed: 02/12/2024] Open
Abstract
One of the most biologically relevant functions of astrocytes within the CNS is the regulation of synaptic transmission, i.e., the physiological basis for information transmission between neurons. Changes in the strength of synaptic connections are indeed thought to be the cellular basis of learning and memory. Importantly, astrocytes have been demonstrated to tightly regulate these processes via the release of several gliotransmitters linked to astrocytic calcium activity as well as astrocyte-neuron metabolic coupling. Therefore, astrocytes seem to be integrators of and actors upon learning- and memory-relevant information. In this review, we focus on the role of astrocytes in learning and memory processes. We delineate the recognized inputs and outputs of astrocytes and explore the influence of manipulating astrocytes on behaviour across diverse learning paradigms. We conclude that astrocytes influence learning and memory in various manners. Appropriate astrocytic Ca2+ dynamics are being increasingly identified as central contributors to memory formation and retrieval. In addition, astrocytes regulate brain rhythms essential for cognition, and astrocyte-neuron metabolic cooperation is required for memory consolidation.
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Affiliation(s)
- Paula Escalada
- Department of Pharmaceutical Sciences, University of Navarra, 31008 Pamplona, Spain; (P.E.); (A.E.); (M.J.R.)
| | - Amaia Ezkurdia
- Department of Pharmaceutical Sciences, University of Navarra, 31008 Pamplona, Spain; (P.E.); (A.E.); (M.J.R.)
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
| | - María Javier Ramírez
- Department of Pharmaceutical Sciences, University of Navarra, 31008 Pamplona, Spain; (P.E.); (A.E.); (M.J.R.)
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
| | - Maite Solas
- Department of Pharmaceutical Sciences, University of Navarra, 31008 Pamplona, Spain; (P.E.); (A.E.); (M.J.R.)
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
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7
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Martins IM, Lima A, de Graaff W, Cristóvão JS, Brosens N, Aronica E, Kluskens LD, Gomes CM, Azeredo J, Kessels HW. M13 phage grafted with peptide motifs as a tool to detect amyloid-β oligomers in brain tissue. Commun Biol 2024; 7:134. [PMID: 38280942 PMCID: PMC10821927 DOI: 10.1038/s42003-024-05806-5] [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: 03/27/2023] [Accepted: 01/11/2024] [Indexed: 01/29/2024] Open
Abstract
Oligomeric clusters of amyloid-β (Aβ) are one of the major biomarkers for Alzheimer's disease (AD). However, proficient methods to detect Aβ-oligomers in brain tissue are lacking. Here we show that synthetic M13 bacteriophages displaying Aβ-derived peptides on their surface preferentially interact with Aβ-oligomers. When exposed to brain tissue isolated from APP/PS1-transgenic mice, these bacteriophages detect small-sized Aβ-aggregates in hippocampus at an early age, prior to the occurrence of Aβ-plaques. Similarly, the bacteriophages reveal the presence of such small Aβ-aggregates in post-mortem hippocampus tissue of AD-patients. These results advocate bacteriophages displaying Aβ-peptides as a convenient and low-cost tool to identify Aβ-oligomers in post-mortem brain tissue of AD-model mice and AD-patients.
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Affiliation(s)
- Ivone M Martins
- CEB- Centre of Biological Engineering, University of Minho, 4710-057, Braga, Portugal.
- LABBELS - Associate Laboratory, Braga/Guimarães, Portugal.
- Netherlands Institute for Neuroscience, Amsterdam, the Netherlands.
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, the Netherlands.
| | - Alexandre Lima
- CEB- Centre of Biological Engineering, University of Minho, 4710-057, Braga, Portugal
- LABBELS - Associate Laboratory, Braga/Guimarães, Portugal
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, the Netherlands
| | - Wim de Graaff
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, the Netherlands
| | - Joana S Cristóvão
- Biosystems & Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
- Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
| | - Niek Brosens
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, the Netherlands
| | - Eleonora Aronica
- Amsterdam UMC location University of Amsterdam, Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam, the Netherlands
| | - Leon D Kluskens
- CEB- Centre of Biological Engineering, University of Minho, 4710-057, Braga, Portugal
- LABBELS - Associate Laboratory, Braga/Guimarães, Portugal
| | - Cláudio M Gomes
- Biosystems & Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
- Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
| | - Joana Azeredo
- CEB- Centre of Biological Engineering, University of Minho, 4710-057, Braga, Portugal
- LABBELS - Associate Laboratory, Braga/Guimarães, Portugal
| | - Helmut W Kessels
- Netherlands Institute for Neuroscience, Amsterdam, the Netherlands.
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, the Netherlands.
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8
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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.
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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.
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9
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Roqué PJ, Barria A, Zhang X, Hashimoto JG, Costa LG, Guizzetti M. Synaptogenesis by Cholinergic Stimulation of Astrocytes. Neurochem Res 2023; 48:3212-3227. [PMID: 37402036 PMCID: PMC10493036 DOI: 10.1007/s11064-023-03979-9] [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: 02/08/2023] [Revised: 05/31/2023] [Accepted: 06/27/2023] [Indexed: 07/05/2023]
Abstract
Astrocytes release numerous factors known to contribute to the process of synaptogenesis, yet knowledge about the signals that control their release is limited. We hypothesized that neuron-derived signals stimulate astrocytes, which respond to neurons through the modulation of astrocyte-released synaptogenic factors. Here we investigate the effect of cholinergic stimulation of astrocytes on synaptogenesis in co-cultured neurons. Using a culture system where primary rat astrocytes and primary rat neurons are first grown separately allowed us to independently manipulate astrocyte cholinergic signaling. Subsequent co-culture of pre-stimulated astrocytes with naïve neurons enabled us to assess how prior stimulation of astrocyte acetylcholine receptors uniquely modulates neuronal synapse formation. Pre-treatment of astrocytes with the acetylcholine receptor agonist carbachol increased the expression of synaptic proteins, the number of pre- and postsynaptic puncta, and the number of functional synapses in hippocampal neurons after 24 h in co-culture. Astrocyte secretion of the synaptogenic protein thrombospondin-1 increased after cholinergic stimulation and inhibition of the receptor for thrombospondins prevented the increase in neuronal synaptic structures. Thus, we identified a novel mechanism of neuron-astrocyte-neuron communication, where neuronal release of acetylcholine stimulates astrocytes to release synaptogenic proteins leading to increased synaptogenesis in neurons. This study provides new insights into the role of neurotransmitter receptors in developing astrocytes and into our understanding of the modulation of astrocyte-induced synaptogenesis.
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Affiliation(s)
- Pamela J Roqué
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
| | - Andrés Barria
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, USA
| | - Xiaolu Zhang
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, USA
- VA Portland Health Care System, Portland, OR, USA
| | - Joel G Hashimoto
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, USA
- VA Portland Health Care System, Portland, OR, USA
| | - Lucio G Costa
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
- Department of Medicine & Surgery, University of Parma, Parma, Italy
| | - Marina Guizzetti
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, USA.
- VA Portland Health Care System, Portland, OR, USA.
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10
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Gebicke-Haerter PJ. The computational power of the human brain. Front Cell Neurosci 2023; 17:1220030. [PMID: 37608987 PMCID: PMC10441807 DOI: 10.3389/fncel.2023.1220030] [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: 05/19/2023] [Accepted: 07/05/2023] [Indexed: 08/24/2023] Open
Abstract
At the end of the 20th century, analog systems in computer science have been widely replaced by digital systems due to their higher computing power. Nevertheless, the question keeps being intriguing until now: is the brain analog or digital? Initially, the latter has been favored, considering it as a Turing machine that works like a digital computer. However, more recently, digital and analog processes have been combined to implant human behavior in robots, endowing them with artificial intelligence (AI). Therefore, we think it is timely to compare mathematical models with the biology of computation in the brain. To this end, digital and analog processes clearly identified in cellular and molecular interactions in the Central Nervous System are highlighted. But above that, we try to pinpoint reasons distinguishing in silico computation from salient features of biological computation. First, genuinely analog information processing has been observed in electrical synapses and through gap junctions, the latter both in neurons and astrocytes. Apparently opposed to that, neuronal action potentials (APs) or spikes represent clearly digital events, like the yes/no or 1/0 of a Turing machine. However, spikes are rarely uniform, but can vary in amplitude and widths, which has significant, differential effects on transmitter release at the presynaptic terminal, where notwithstanding the quantal (vesicular) release itself is digital. Conversely, at the dendritic site of the postsynaptic neuron, there are numerous analog events of computation. Moreover, synaptic transmission of information is not only neuronal, but heavily influenced by astrocytes tightly ensheathing the majority of synapses in brain (tripartite synapse). At least at this point, LTP and LTD modifying synaptic plasticity and believed to induce short and long-term memory processes including consolidation (equivalent to RAM and ROM in electronic devices) have to be discussed. The present knowledge of how the brain stores and retrieves memories includes a variety of options (e.g., neuronal network oscillations, engram cells, astrocytic syncytium). Also epigenetic features play crucial roles in memory formation and its consolidation, which necessarily guides to molecular events like gene transcription and translation. In conclusion, brain computation is not only digital or analog, or a combination of both, but encompasses features in parallel, and of higher orders of complexity.
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Affiliation(s)
- Peter J. Gebicke-Haerter
- Institute of Psychopharmacology, Central Institute of Mental Health, Faculty of Medicine, University of Heidelberg, Mannheim, Germany
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11
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Pereira MJ, Ayana R, Holt MG, Arckens L. Chemogenetic manipulation of astrocyte activity at the synapse- a gateway to manage brain disease. Front Cell Dev Biol 2023; 11:1193130. [PMID: 37534103 PMCID: PMC10393042 DOI: 10.3389/fcell.2023.1193130] [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: 03/24/2023] [Accepted: 06/14/2023] [Indexed: 08/04/2023] Open
Abstract
Astrocytes are the major glial cell type in the central nervous system (CNS). Initially regarded as supportive cells, it is now recognized that this highly heterogeneous cell population is an indispensable modulator of brain development and function. Astrocytes secrete neuroactive molecules that regulate synapse formation and maturation. They also express hundreds of G protein-coupled receptors (GPCRs) that, once activated by neurotransmitters, trigger intracellular signalling pathways that can trigger the release of gliotransmitters which, in turn, modulate synaptic transmission and neuroplasticity. Considering this, it is not surprising that astrocytic dysfunction, leading to synaptic impairment, is consistently described as a factor in brain diseases, whether they emerge early or late in life due to genetic or environmental factors. Here, we provide an overview of the literature showing that activation of genetically engineered GPCRs, known as Designer Receptors Exclusively Activated by Designer Drugs (DREADDs), to specifically modulate astrocyte activity partially mimics endogenous signalling pathways in astrocytes and improves neuronal function and behavior in normal animals and disease models. Therefore, we propose that expressing these genetically engineered GPCRs in astrocytes could be a promising strategy to explore (new) signalling pathways which can be used to manage brain disorders. The precise molecular, functional and behavioral effects of this type of manipulation, however, differ depending on the DREADD receptor used, targeted brain region and timing of the intervention, between healthy and disease conditions. This is likely a reflection of regional and disease/disease progression-associated astrocyte heterogeneity. Therefore, a thorough investigation of the effects of such astrocyte manipulation(s) must be conducted considering the specific cellular and molecular environment characteristic of each disease and disease stage before this has therapeutic applicability.
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Affiliation(s)
- Maria João Pereira
- Department of Biology, Laboratory of Neuroplasticity and Neuroproteomics, KU Leuven, Leuven, Belgium
- KU Leuven Brain Institute, Leuven, Belgium
| | - Rajagopal Ayana
- Department of Biology, Laboratory of Neuroplasticity and Neuroproteomics, KU Leuven, Leuven, Belgium
- KU Leuven Brain Institute, Leuven, Belgium
| | - Matthew G. Holt
- Instituto de Investigação e Inovação em Saúde (i3S), Laboratory of Synapse Biology, Universidade do Porto, Porto, Portugal
| | - Lutgarde Arckens
- Department of Biology, Laboratory of Neuroplasticity and Neuroproteomics, KU Leuven, Leuven, Belgium
- KU Leuven Brain Institute, Leuven, Belgium
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12
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Nanclares C, Poynter J, Martell-Martinez HA, Vermilyea S, Araque A, Kofuji P, Lee MK, Covelo A. Dysregulation of astrocytic Ca 2+ signaling and gliotransmitter release in mouse models of α-synucleinopathies. Acta Neuropathol 2023; 145:597-610. [PMID: 36764943 PMCID: PMC10119048 DOI: 10.1007/s00401-023-02547-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/17/2023] [Accepted: 02/01/2023] [Indexed: 02/12/2023]
Abstract
α-Synuclein is a major component of Lewy bodies (LB) and Lewy neurites (LN) appearing in the postmortem brain of Parkinson's disease (PD) and other α-synucleinopathies. While most studies of α-synucleinopathies have focused on neuronal and synaptic alterations as well as dysfunctions of the astrocytic homeostatic roles, whether the bidirectional astrocyte-neuronal communication is affected in these diseases remains unknown. We have investigated whether the astrocyte Ca2+ excitability and the glutamatergic gliotransmission underlying astrocyte-neuronal signaling are altered in several transgenic mouse models related to α-synucleinopathies, i.e., mice expressing high and low levels of the human A53T mutant α-synuclein (G2-3 and H5 mice, respectively) globally or selectively in neurons (iSyn mice), mice expressing human wildtype α-synuclein (I2-2 mice), and mice expressing A30P mutant α-synuclein (O2 mice). Combining astrocytic Ca2+ imaging and neuronal electrophysiological recordings in hippocampal slices of these mice, we have found that compared to non-transgenic mice, astrocytes in G2-3 mice at different ages (1-6 months) displayed a Ca2+ hyperexcitability that was independent of neurotransmitter receptor activation, suggesting that the expression of α-synuclein mutant A53T altered the intrinsic properties of astrocytes. Similar dysregulation of the astrocyte Ca2+ signal was present in H5 mice, but not in I2-2 and O2 mice, indicating α-synuclein mutant-specific effects. Moreover, astrocyte Ca2+ hyperexcitability was absent in mice expressing the α-synuclein mutant A53T selectively in neurons, indicating that the effects on astrocytes were cell-autonomous. Consistent with these effects, glutamatergic gliotransmission was enhanced in G2-3 and H5 mice, but was unaffected in I2-2, O2 and iSyn mice. These results indicate a cell-autonomous effect of pathogenic A53T expression in astrocytes that may contribute to the altered neuronal and synaptic function observed in α-synucleinopathies.
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Affiliation(s)
- Carmen Nanclares
- Department of Neuroscience, University of Minnesota, 4-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA
| | - Jonah Poynter
- Department of Neuroscience, University of Minnesota, 4-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA
| | - Hector A Martell-Martinez
- Department of Neuroscience, University of Minnesota, 4-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA
| | - Scott Vermilyea
- Department of Neuroscience, University of Minnesota, 4-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA
- Institute for Translational Neuroscience, University of Minnesota, 2101 6th Street SE, Minneapolis, MN, 55455, USA
| | - Alfonso Araque
- Department of Neuroscience, University of Minnesota, 4-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA
| | - Paulo Kofuji
- Department of Neuroscience, University of Minnesota, 4-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA.
| | - Michael K Lee
- Department of Neuroscience, University of Minnesota, 4-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA.
- Institute for Translational Neuroscience, University of Minnesota, 2101 6th Street SE, Minneapolis, MN, 55455, USA.
| | - Ana Covelo
- Department of Neuroscience, University of Minnesota, 4-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA.
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1215 NeuroCentre Magendie, 33077, Bordeaux, France.
- University of Bordeaux, 33077, Bordeaux, France.
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13
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Dempsey LM, Kavanagh JJ. Muscarinic acetylcholine activity modulates cortical silent period, but not motor evoked potentials, during muscle contractions. Exp Brain Res 2023; 241:1543-1553. [PMID: 37103494 DOI: 10.1007/s00221-023-06616-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 04/11/2023] [Indexed: 04/28/2023]
Abstract
This study used transcranial magnetic stimulation (TMS) to determine if muscarinic receptor blockade affects muscle responses during voluntary contractions. Motor evoked potentials (MEPs) were recorded from biceps brachii in 10 subjects (age: 23 ± 2) during 10%, 25%, 50%, 75%, and 100% maximal voluntary contractions (MVCs). Each contraction intensity was examined under non-fatigued and fatigued conditions. All measurements were obtained post-ingestion of 25 mg promethazine or placebo. MEP area and the duration of the TMS-evoked silent period (SP) were calculated for all contractions. No drug-related differences were detected for MEP area during non-fatigued or fatigued contractions. A main effect of drug was detected for the SP (p = 0.019) where promethazine increased SP duration by an average of 0.023 [Formula: see text] 0.015 s. This drug effect was only identified for the unfatigued contractions and not following the sustained fatiguing contractions (p = 0.105). The cholinergic system does not influence corticospinal excitability during voluntary muscle contractions, but instead affects neural circuits associated with the TMS-evoked SP. Given the prevalence of cholinergic properties in prescription and over-the-counter medications, the current study enhances our understanding of mechanisms that may contribute to motor side-effects.
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Affiliation(s)
- Lisa M Dempsey
- Menzies Health Institute Queensland, Griffith University, Southport, Australia.
- School of Allied Health Sciences, Griffith University, Gold Coast Campus, Southport, QLD, 4222, Australia.
| | - Justin J Kavanagh
- Menzies Health Institute Queensland, Griffith University, Southport, Australia
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14
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Olson ML, Badenoch B, Blatti M, Buching C, Glewwe N. Muscarinic Cholinergic Receptor Antagonism Impairs Spatial Memory Retrieval and Minimizes Retrieval-Induced Alterations in Matrix Metalloproteinase-9. Behav Brain Res 2023; 448:114460. [PMID: 37119978 DOI: 10.1016/j.bbr.2023.114460] [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: 11/27/2022] [Revised: 04/26/2023] [Accepted: 04/26/2023] [Indexed: 05/01/2023]
Abstract
Cholinergic dysfunction in the hippocampus causes memory impairment, and degradation of the forebrain cholinergic system has been implicated in several neurological disorders. One such disorder, Alzheimer's Disease (AD) is associated with the abnormal expression of various proteins including matrix metalloproteinase-9 (MMP-9), an enzyme known to regulate hippocampus-dependent memory. Memory involves several stages including acquisition, consolidation, and retrieval, but the neurobiological correlates of retrieval have been studied much less than other stages of memory. We sought to investigate the potential relationship between cholinergic signaling and hippocampal MMP-9 expression and the involvement of each in spatial memory retrieval. We trained rats in the water maze until the task was well-learned, then, seven days later, we allowed some to retrieve the memory after an intracerebroventricular injection of scopolamine or vehicle. Western blot analysis of hippocampal tissue shows elevated levels of a truncated form of MMP-9 associated with spatial memory retrieval. Additionally, our results indicate that centrally administered scopolamine both impairs spatial memory retrieval and prevents retrieval-induced elevations in MMP-9. These findings provide evidence for a potential link between cholinergic dysregulation and abnormal MMP-9 levels seen in the brains of AD patients. An important, yet unresolved question is whether MMP-9 serves to support memory retrieval itself or if it is involved in maintaining the ongoing stability of a retrieved memory.
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Affiliation(s)
- Mikel L Olson
- Department of Psychology, Concordia College, Moorhead, MN.
| | | | - Megan Blatti
- Department of Psychology, Concordia College, Moorhead, MN.
| | | | - Nic Glewwe
- Department of Psychology, Concordia College, Moorhead, MN.
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15
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Roqué PJ, Barria A, Zhang X, Costa LG, Guizzetti M. Synaptogenesis by Cholinergic Stimulation of Astrocytes. RESEARCH SQUARE 2023:rs.3.rs-2566078. [PMID: 36824819 PMCID: PMC9949182 DOI: 10.21203/rs.3.rs-2566078/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Astrocytes release numerous factors known to contribute to the process of synaptogenesis, yet knowledge about the signals that control their release is limited. We hypothesized that neuron-derived signals stimulate astrocytes, which respond by signaling back to neurons through the modulation of astrocyte-released synaptogenic factors. Here we investigate the effect of cholinergic stimulation of astrocytes on synaptogenesis in co-cultured neurons. Using a culture system where primary rat astrocytes and primary rat neurons are first grown separately allowed us to independently manipulate astrocyte cholinergic signaling. Subsequent co-culture of pre-stimulated astrocytes with naïve neurons enabled us to assess how prior stimulation of astrocyte acetylcholine receptors uniquely modulates neuronal synapse formation. Pre-treatment of astrocytes with the acetylcholine receptor agonist carbachol increased the expression of synaptic proteins, the number of pre- and postsynaptic puncta, and the number of functional synapses in hippocampal neurons after 24 hours in co-culture. Astrocyte secretion of the synaptogenic protein thrombospondin-1 increased after cholinergic stimulation and the inhibition of the target receptor for thrombospondins prevented the observed increase in neuronal synaptic structures. Thus, we identified a novel mechanism of neuron-astrocyte-neuron communication, i.e. , neuronal release of acetylcholine stimulates astrocytes to release synaptogenic proteins leading to increased synaptogenesis in neurons. This study provides new insights into the role of neurotransmitter receptors in developing astrocytes and into our understanding of the modulation of astrocyte-induced synaptogenesis.
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16
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Vezzani A, Ravizza T, Bedner P, Aronica E, Steinhäuser C, Boison D. Astrocytes in the initiation and progression of epilepsy. Nat Rev Neurol 2022; 18:707-722. [PMID: 36280704 PMCID: PMC10368155 DOI: 10.1038/s41582-022-00727-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/16/2022] [Indexed: 11/09/2022]
Abstract
Epilepsy affects ~65 million people worldwide. First-line treatment options include >20 antiseizure medications, but seizure control is not achieved in approximately one-third of patients. Antiseizure medications act primarily on neurons and can provide symptomatic control of seizures, but do not alter the onset and progression of epilepsy and can cause serious adverse effects. Therefore, medications with new cellular and molecular targets and mechanisms of action are needed. Accumulating evidence indicates that astrocytes are crucial to the pathophysiological mechanisms of epilepsy, raising the possibility that these cells could be novel therapeutic targets. In this Review, we discuss how dysregulation of key astrocyte functions - gliotransmission, cell metabolism and immune function - contribute to the development and progression of hyperexcitability in epilepsy. We consider strategies to mitigate astrocyte dysfunction in each of these areas, and provide an overview of how astrocyte activation states can be monitored in vivo not only to assess their contribution to disease but also to identify markers of disease processes and treatment effects. Improved understanding of the roles of astrocytes in epilepsy has the potential to lead to novel therapies to prevent the initiation and progression of epilepsy.
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Affiliation(s)
- Annamaria Vezzani
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milano, Italy.
| | - Teresa Ravizza
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milano, Italy
| | - Peter Bedner
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Eleonora Aronica
- Amsterdam UMC, University of Amsterdam, Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam, Netherlands
- Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, Netherlands
| | - Christian Steinhäuser
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Detlev Boison
- Department of Neurosurgery, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, USA
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17
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Mederos S, Sánchez-Ruiz A, Perea G. Protocol to downregulate GABAergic-astrocyte signaling via astrocyte-selective ablation of GABA B receptor in adult mice. STAR Protoc 2022; 3:101667. [PMID: 36103305 PMCID: PMC9483643 DOI: 10.1016/j.xpro.2022.101667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 07/07/2022] [Accepted: 08/03/2022] [Indexed: 01/25/2023] Open
Abstract
Here, we present a protocol to selectively downregulate GABAB receptor (GABABR) expression in astrocytes of mouse medial prefrontal cortex (mPFC). We first describe the procedure of surgeries and viral injections. We then detail genetic, histological, and functional characterizations of astrocytic GABABR ablation using RT-PCR, imaging, and behavioral assays. The use of GABAB flox mice can be easily adapted to generate astrocyte-selective GABABR ablation in different brain areas and postnatal stages, leading to local downregulation of GABAergic-astrocyte signaling without developmental issues. For complete details on the use and execution of this protocol, please refer to Mederos et al. (2021).
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Affiliation(s)
- Sara Mederos
- Sainsbury Wellcome Centre for Neural Circuits and Behaviour, University College London, London W1T 4JG, UK,Corresponding author
| | | | - Gertrudis Perea
- Neuron-Glia Networks Lab. Cajal Institute, CSIC, Madrid 28002, Spain,Corresponding author
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18
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Ca 2+-modulated photoactivatable imaging reveals neuron-astrocyte glutamatergic circuitries within the nucleus accumbens. Nat Commun 2022; 13:5272. [PMID: 36071061 PMCID: PMC9452556 DOI: 10.1038/s41467-022-33020-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 08/25/2022] [Indexed: 11/11/2022] Open
Abstract
Astrocytes are key elements of brain circuits that are involved in different aspects of the neuronal physiology relevant to brain functions. Although much effort is being made to understand how the biology of astrocytes affects brain circuits, astrocytic network heterogeneity and plasticity is still poorly defined. Here, we have combined structural and functional imaging of astrocyte activity recorded in mice using the Ca2+-modulated photoactivatable ratiometric integrator and specific optostimulation of glutamatergic pathways to map the functional neuron-astrocyte circuitries in the nucleus accumbens (NAc). We showed pathway-specific astrocytic responses induced by selective optostimulation of main inputs from the prefrontal cortex, basolateral amygdala, and ventral hippocampus. Furthermore, co-stimulation of glutamatergic pathways induced non-linear Ca2+-signaling integration, revealing integrative properties of NAc astrocytes. All these results demonstrate the existence of specific neuron-astrocyte circuits in the NAc, providing an insight to the understanding of how the NAc integrates information. Neuron-astrocyte communication is fundamental for brain physiology, yet the heterogeneity in the functional interaction between these two elements remains poorly understood. Here we show how different neuron-astrocyte networks integrate information from distinct glutamatergic inputs.
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19
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Emerging Role of Neuron-Glia in Neurological Disorders: At a Glance. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:3201644. [PMID: 36046684 PMCID: PMC9423989 DOI: 10.1155/2022/3201644] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 08/05/2022] [Indexed: 11/18/2022]
Abstract
Based on the diverse physiological influence, the impact of glial cells has become much more evident on neurological illnesses, resulting in the origins of many diseases appearing to be more convoluted than previously happened. Since neurological disorders are often random and unknown, hence the construction of animal models is difficult to build, representing a small fraction of people with a gene mutation. As a result, an immediate necessity is grown to work within in vitro techniques for examining these illnesses. As the scientific community recognizes cell-autonomous contributions to a variety of central nervous system illnesses, therapeutic techniques involving stem cells for treating neurological diseases are gaining traction. The use of stem cells derived from a variety of sources is increasingly being used to replace both neuronal and glial tissue. The brain's energy demands necessitate the reliance of neurons on glial cells in order for it to function properly. Furthermore, glial cells have diverse functions in terms of regulating their own metabolic activities, as well as collaborating with neurons via secreted signaling or guidance molecules, forming a complex network of neuron-glial connections in health and sickness. Emerging data reveals that metabolic changes in glial cells can cause morphological and functional changes in conjunction with neuronal dysfunction under disease situations, highlighting the importance of neuron-glia interactions in the pathophysiology of neurological illnesses. In this context, it is required to improve our understanding of disease mechanisms and create potential novel therapeutics. According to research, synaptic malfunction is one of the features of various mental diseases, and glial cells are acting as key ingredients not only in synapse formation, growth, and plasticity but also in neuroinflammation and synaptic homeostasis which creates critical physiological capacity in the focused sensory system. The goal of this review article is to elaborate state-of-the-art information on a few glial cell types situated in the central nervous system (CNS) and highlight their role in the onset and progression of neurological disorders.
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20
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Dias L, Madeira D, Dias R, Tomé ÂR, Cunha RA, Agostinho P. Aβ 1-42 peptides blunt the adenosine A 2A receptor-mediated control of the interplay between P 2X 7 and P 2Y 1 receptors mediated calcium responses in astrocytes. Cell Mol Life Sci 2022; 79:457. [PMID: 35907034 PMCID: PMC11071907 DOI: 10.1007/s00018-022-04492-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 06/22/2022] [Accepted: 07/15/2022] [Indexed: 12/21/2022]
Abstract
The contribution of astrocytes to Alzheimer's disease (AD) is still ill defined. AD involves an abnormal accumulation of amyloid-β peptides (Aβ) and increased production of danger signals such as ATP. ATP can direct or indirectly, through its metabolism into adenosine, trigger adaptive astrocytic responses resulting from intracellular Ca2+ oscillations. AD also triggers an upregulation of astrocytic adenosine A2A receptors (A2AR), which blockade prevents memory dysfunction in AD. We now investigated how Aβ peptides affect ATP-mediated Ca2+ responses in astrocytes measured by fluorescence live-cell imaging and whether A2AR control astrocytic Ca2+ responses mediated by ATP receptors, mainly P2X7R and P2Y1R. In primary cultures of rat astrocytes exposed to Aβ1-42, ATP-evoked Ca2+ responses had a lower amplitude but a longer duration than in control astrocytes and involved P2X7R and P2Y1R, the former potentiating the later. Moreover, Aβ1-42 exposure increased protein levels of P2Y1R in astrocytes. A2AR antagonism with SCH58261 controlled in a protein kinase A-dependent manner both P2X7R- and P2Y1R-mediated Ca2+ responses in astrocytes. The interplay between these purinoceptors in astrocytes was blunted upon exposure to Aβ1-42. These findings uncover the ability of A2AR to regulate the inter-twinned P2X7R- and P2Y1R-mediated Ca2+ dynamics in astrocytes, which is disrupted in conditions of early AD.
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Affiliation(s)
- Liliana Dias
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Rua Larga, Polo I FMUC, 1st Floor, 3004-504, Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, Rua Larga, Polo I FMUC, 1st Floor, 3004-504, Coimbra, Portugal
| | - Daniela Madeira
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Rua Larga, Polo I FMUC, 1st Floor, 3004-504, Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, Rua Larga, Polo I FMUC, 1st Floor, 3004-504, Coimbra, Portugal
| | - Rafael Dias
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Rua Larga, Polo I FMUC, 1st Floor, 3004-504, Coimbra, Portugal
| | - Ângelo R Tomé
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Rua Larga, Polo I FMUC, 1st Floor, 3004-504, Coimbra, Portugal
- Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Coimbra, Portugal
| | - Rodrigo A Cunha
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Rua Larga, Polo I FMUC, 1st Floor, 3004-504, Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, Rua Larga, Polo I FMUC, 1st Floor, 3004-504, Coimbra, Portugal
| | - Paula Agostinho
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Rua Larga, Polo I FMUC, 1st Floor, 3004-504, Coimbra, Portugal.
- Faculty of Medicine, University of Coimbra, Rua Larga, Polo I FMUC, 1st Floor, 3004-504, Coimbra, Portugal.
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21
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Pandey P, Kaur G, Babu K. Crosstalk between neurons and glia through G-protein coupled receptors: Insights from Caenorhabditis elegans. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2022; 193:119-144. [PMID: 36357074 DOI: 10.1016/bs.pmbts.2022.06.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The past decades have witnessed a dogmatic shift from glia as supporting cells in the nervous system to their active roles in neurocentric functions. Neurons and glia communicate and show bidirectional responses through tripartite synapses. Studies across species indicate that neurotransmitters released by neurons are perceived by glial receptors, which allow for gliotransmitter release. These gliotransmitters can result in activation of neurons via neuronal GPCR receptors. However, studies of these molecular interactions are in their infancy. Caenorhabditis elegans has a conserved neuron-glia architectural repertoire with molecular and functional resemblance to mammals. Further, glia in C. elegans can be manipulated through ablation and mutations allowing for deciphering of glial dependent processes in vivo at single glial resolutions. Here, we will review recent findings from vertebrate and invertebrate organisms with a focus on how C. elegans can be used to advance our understanding of neuron-glia interactions through GPCRs.
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Affiliation(s)
- Pratima Pandey
- Indian Institute of Science Education and Research, Mohali, Punjab, India.
| | - Gazaldeep Kaur
- National Agri-Food Biotechnology Institute, Mohali, Punjab, India
| | - Kavita Babu
- Indian Institute of Science, Bangalore, Karnataka, India.
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22
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Malfunction of astrocyte and cholinergic input is involved in postoperative impairment of hippocampal synaptic plasticity and cognitive function. Neuropharmacology 2022; 217:109191. [PMID: 35835213 DOI: 10.1016/j.neuropharm.2022.109191] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 06/04/2022] [Accepted: 07/07/2022] [Indexed: 12/28/2022]
Abstract
Postoperative delirium (POD) occurs in a few days after major surgery under general anesthesia and may cause serious health problems. However, effective intervention and treatment remain unavailable because the underlying mechanisms have far been elucidated. In the present study, we explored the role of the malfunctioned astrocytes in POD. Our results showed that mice with tibia fracture displayed spatial and temporal memory impairments, reduced LTP, and activated astrocytes in the hippocampus in early postoperative stage. Using electrophysiological and Ca2+ imaging techniques in hippocampal slices, we demonstrated the malfunctions of astrocytes in surgery mice: depolarized resting membrane potential, higher membrane conductance and capacitance, and attenuated Ca2+ elevation in response to external stimulation. The degraded calcium signaling in hippocampal astrocytes in surgery mice was restored by correcting the diminution of acetylcholine release with galantamine. Furthermore, pharmacologically blocking astrocyte activation with fluorocitrate and enhancing cholinergic inputs with galantamine normalized hippocampal LTP in surgery mice. Finally, inhibition of astrocyte activation with fluorocitrate in the hippocampus improved cognitive function in surgery mice. Therefore, the prevention of astrocyte activation may be a valuable strategy for the intervention of cognitive dysfunction in POD, and acetylcholine receptors may be valid drug targets for this purpose.
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23
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Huang Q, Liao C, Ge F, Ao J, Liu T. Acetylcholine bidirectionally regulates learning and memory. JOURNAL OF NEURORESTORATOLOGY 2022. [DOI: 10.1016/j.jnrt.2022.100002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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24
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de la Cruz L, Kushmerick C, Sullivan JM, Kruse M, Vivas O. Hippocampal neurons maintain a large PtdIns(4)P pool that results in faster PtdIns(4,5)P2 synthesis. J Gen Physiol 2022; 154:213016. [PMID: 35179558 PMCID: PMC8906353 DOI: 10.1085/jgp.202113001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 01/01/2022] [Accepted: 01/24/2022] [Indexed: 12/24/2022] Open
Abstract
PtdIns(4,5)P2 is a signaling lipid central to the regulation of multiple cellular functions. It remains unknown how PtdIns(4,5)P2 fulfills various functions in different cell types, such as regulating neuronal excitability, synaptic release, and astrocytic function. Here, we compared the dynamics of PtdIns(4,5)P2 synthesis in hippocampal neurons and astrocytes with the kidney-derived tsA201 cell line. The experimental approach was to (1) measure the abundance and rate of PtdIns(4,5)P2 synthesis and precursors using specific biosensors, (2) measure the levels of PtdIns(4,5)P2 and its precursors using mass spectrometry, and (3) use a mathematical model to compare the metabolism of PtdIns(4,5)P2 in cell types with different proportions of phosphoinositides. The rate of PtdIns(4,5)P2 resynthesis in hippocampal neurons after depletion by cholinergic or glutamatergic stimulation was three times faster than for tsA201 cells. In tsA201 cells, resynthesis of PtdIns(4,5)P2 was dependent on the enzyme PI4K. In contrast, in hippocampal neurons, the resynthesis rate of PtdIns(4,5)P2 was insensitive to the inhibition of PI4K, indicating that it does not require de novo synthesis of the precursor PtdIns(4)P. Measurement of phosphoinositide abundance indicated a larger pool of PtdIns(4)P, suggesting that hippocampal neurons maintain sufficient precursor to restore PtdIns(4,5)P2 levels. Quantitative modeling indicates that the measured differences in PtdIns(4)P pool size and higher activity of PI4K can account for the experimental findings and indicates that high PI4K activity prevents depletion of PtdIns(4)P. We further show that the resynthesis of PtdIns(4,5)P2 is faster in neurons than astrocytes, providing context to the relevance of cell type–specific mechanisms to sustain PtdIns(4,5)P2 levels.
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Affiliation(s)
- Lizbeth de la Cruz
- Department of Physiology and Biophysics, University of Washington, Seattle, WA
| | - Christopher Kushmerick
- Department of Physiology and Biophysics, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Jane M Sullivan
- Department of Physiology and Biophysics, University of Washington, Seattle, WA
| | - Martin Kruse
- Department of Biology and Program in Neuroscience, Bates College, Lewiston, ME
| | - Oscar Vivas
- Department of Physiology and Biophysics, University of Washington, Seattle, WA
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25
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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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Shimoda Y, Beppu K, Ikoma Y, Morizawa YM, Zuguchi S, Hino U, Yano R, Sugiura Y, Moritoh S, Fukazawa Y, Suematsu M, Mushiake H, Nakasato N, Iwasaki M, Tanaka KF, Tominaga T, Matsui K. Optogenetic stimulus-triggered acquisition of seizure resistance. Neurobiol Dis 2021; 163:105602. [PMID: 34954320 DOI: 10.1016/j.nbd.2021.105602] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 12/21/2021] [Accepted: 12/22/2021] [Indexed: 11/26/2022] Open
Abstract
Unlike an electrical circuit, the hardware of the brain is susceptible to change. Repeated electrical brain stimulation mimics epileptogenesis. After such "kindling" process, a moderate stimulus would become sufficient in triggering a severe seizure. Here, we report that optogenetic neuronal stimulation can also convert the rat brain to a hyperexcitable state. However, continued stimulation once again converted the brain to a state that was strongly resistant to seizure induction. Histochemical examinations showed that moderate astrocyte activation was coincident with resilience acquisition. Administration of an adenosine A1 receptor antagonist instantly reverted the brain back to a hyperexcitable state, suggesting that hyperexcitability was suppressed by adenosine. Furthermore, an increase in basal adenosine was confirmed using in vivo microdialysis. Daily neuron-to-astrocyte signaling likely prompted a homeostatic increase in the endogenous actions of adenosine. Our data suggest that a certain stimulation paradigm could convert the brain circuit resilient to epilepsy without exogenous drug administration.
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Affiliation(s)
- Yoshiteru Shimoda
- Division of Interdisciplinary Medical Science, Center for Neuroscience, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan; Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Kaoru Beppu
- Division of Interdisciplinary Medical Science, Center for Neuroscience, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Yoko Ikoma
- Super-network Brain Physiology, Tohoku University Graduate School of Life Sciences, Sendai 980-8577, Japan
| | - Yosuke M Morizawa
- Division of Interdisciplinary Medical Science, Center for Neuroscience, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan; Super-network Brain Physiology, Tohoku University Graduate School of Life Sciences, Sendai 980-8577, Japan
| | - Satoshi Zuguchi
- Division of Interdisciplinary Medical Science, Center for Neuroscience, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Utaro Hino
- Department of Neuropsychiatry, School of Medicine, Keio University, Tokyo 160-8582, Japan
| | - Ryutaro Yano
- Department of Neuropsychiatry, School of Medicine, Keio University, Tokyo 160-8582, Japan
| | - Yuki Sugiura
- Department of Biochemistry & Integrative Medical Biology, School of Medicine, Keio University, Tokyo 160-8582, Japan
| | - Satoru Moritoh
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Yugo Fukazawa
- Division of Cell Biology and Neuroscience, University of Fukui Faculty of Medical Sciences, Fukui 910-1193, Japan
| | - Makoto Suematsu
- Department of Biochemistry & Integrative Medical Biology, School of Medicine, Keio University, Tokyo 160-8582, Japan
| | - Hajime Mushiake
- Department of Physiology, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Nobukazu Nakasato
- Department of Epileptology, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Masaki Iwasaki
- Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Kenji F Tanaka
- Department of Neuropsychiatry, School of Medicine, Keio University, Tokyo 160-8582, Japan
| | - Teiji Tominaga
- Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Ko Matsui
- Division of Interdisciplinary Medical Science, Center for Neuroscience, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan; Super-network Brain Physiology, Tohoku University Graduate School of Life Sciences, Sendai 980-8577, Japan.
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Pallen S, Shetty Y, Das S, Vaz JM, Mazumder N. Advances in nonlinear optical microscopy techniques for in vivo and in vitro neuroimaging. Biophys Rev 2021; 13:1199-1217. [PMID: 35047093 PMCID: PMC8724370 DOI: 10.1007/s12551-021-00832-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 08/17/2021] [Indexed: 11/27/2022] Open
Abstract
Understanding the mechanism of the brain via optical microscopy is one of the challenges in neuroimaging, considering the complex structures. Advanced neuroimaging techniques provide a more comprehensive insight into patho-mechanisms of brain disorders, which is useful in the early diagnosis of the pathological and physiological changes associated with various neurodegenerative diseases. Recent advances in optical microscopy techniques have evolved powerful tools to overcome scattering of light and provide improved in vivo neuroimaging with sub-cellular resolution, endogenous contrast specificity, pinhole less optical sectioning capability, high penetration depth, and so on. The following article reviews the developments in various optical imaging techniques including two-photon and three-photon fluorescence, second-harmonic generation, third-harmonic generation, coherent anti-Stokes Raman scattering, and stimulated Raman scattering in neuroimaging. We have outlined the potentials and drawbacks of these techniques and their possible applications in the investigation of neurodegenerative diseases.
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Affiliation(s)
- Sparsha Pallen
- Department of Biophysics, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka 576104 India
| | - Yuthika Shetty
- Department of Biophysics, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka 576104 India
| | - Subir Das
- Institute of Biophotonics, National Yang Ming Chiao Tung University, No. 155, Sec. 2, Linong St., Taipei, 112 Taiwan
| | - Joel Markus Vaz
- Department of Biotechnology, Manipal Institute of Technology, Manipal, Karnataka 576104 India
| | - Nirmal Mazumder
- Department of Biophysics, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka 576104 India
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Liu X, Ying J, Wang X, Zheng Q, Zhao T, Yoon S, Yu W, Yang D, Fang Y, Hua F. Astrocytes in Neural Circuits: Key Factors in Synaptic Regulation and Potential Targets for Neurodevelopmental Disorders. Front Mol Neurosci 2021; 14:729273. [PMID: 34658786 PMCID: PMC8515196 DOI: 10.3389/fnmol.2021.729273] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 09/02/2021] [Indexed: 12/14/2022] Open
Abstract
Astrocytes are the major glial cells in the brain, which play a supporting role in the energy and nutritional supply of neurons. They were initially regarded as passive space-filling cells, but the latest progress in the study of the development and function of astrocytes highlights their active roles in regulating synaptic transmission, formation, and plasticity. In the concept of "tripartite synapse," the bidirectional influence between astrocytes and neurons, in addition to their steady-state and supporting function, suggests that any negative changes in the structure or function of astrocytes will affect the activity of neurons, leading to neurodevelopmental disorders. The role of astrocytes in the pathophysiology of various neurological and psychiatric disorders caused by synaptic defects is increasingly appreciated. Understanding the roles of astrocytes in regulating synaptic development and the plasticity of neural circuits could help provide new treatments for these diseases.
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Affiliation(s)
- Xing Liu
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, China
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang, China
| | - Jun Ying
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, China
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang, China
| | - Xifeng Wang
- Department of Anesthesiology, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Qingcui Zheng
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, China
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang, China
| | - Tiancheng Zhao
- Mailman School of Public Health, Columbia University, New York, NY, United States
| | - Sungtae Yoon
- Helping Minds International Charitable Foundation, New York, NY, United States
| | - Wen Yu
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, China
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang, China
| | - Danying Yang
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, China
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang, China
| | - Yang Fang
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, China
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang, China
| | - Fuzhou Hua
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, China
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang, China
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Akther S, Hirase H. Assessment of astrocytes as a mediator of memory and learning in rodents. Glia 2021; 70:1484-1505. [PMID: 34582594 DOI: 10.1002/glia.24099] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 09/15/2021] [Accepted: 09/16/2021] [Indexed: 12/26/2022]
Abstract
The classical view of astrocytes is that they provide supportive functions for neurons, transporting metabolites and maintaining the homeostasis of the extracellular milieu. This view is gradually changing with the advent of molecular genetics and optical methods allowing interrogation of selected cell types in live experimental animals. An emerging view that astrocytes additionally act as a mediator of synaptic plasticity and contribute to learning processes has gained in vitro and in vivo experimental support. Here we focus on the literature published in the past two decades to review the roles of astrocytes in brain plasticity in rodents, whereby the roles of neurotransmitters and neuromodulators are considered to be comparable to those in humans. We outline established inputs and outputs of astrocytes and discuss how manipulations of astrocytes have impacted the behavior in various learning paradigms. Multiple studies suggest that the contribution of astrocytes has a considerably longer time course than neuronal activation, indicating metabolic roles of astrocytes. We advocate that exploring upstream and downstream mechanisms of astrocytic activation will further provide insight into brain plasticity and memory/learning impairment.
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Affiliation(s)
- Sonam Akther
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hajime Hirase
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Glial glucose fuels the neuronal pentose phosphate pathway for long-term memory. Cell Rep 2021; 36:109620. [PMID: 34433052 PMCID: PMC8411112 DOI: 10.1016/j.celrep.2021.109620] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 07/22/2021] [Accepted: 08/05/2021] [Indexed: 01/10/2023] Open
Abstract
Brain function relies almost solely on glucose as an energy substrate. The main model of brain metabolism proposes that glucose is taken up and converted into lactate by astrocytes to fuel the energy-demanding neuronal activity underlying plasticity and memory. Whether direct neuronal glucose uptake is required for memory formation remains elusive. We uncover, in Drosophila, a mechanism of glucose shuttling to neurons from cortex glia, an exclusively perisomatic glial subtype, upon formation of olfactory long-term memory (LTM). In vivo imaging reveals that, downstream of cholinergic activation of cortex glia, autocrine insulin signaling increases glucose concentration in glia. Glucose is then transferred from glia to the neuronal somata in the olfactory memory center to fuel the pentose phosphate pathway and allow LTM formation. In contrast, our results indicate that the increase in neuronal glucose metabolism, although crucial for LTM formation, is not routed to glycolysis. Neuronal glucose metabolism is increased upon long-term memory formation Glial cells shuttle glucose to neurons following insulin signaling activation Glucose fuels the neuronal pentose phosphate pathway
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31
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Astrocytic contribution to glutamate-related central respiratory chemoreception in vertebrates. Respir Physiol Neurobiol 2021; 294:103744. [PMID: 34302992 DOI: 10.1016/j.resp.2021.103744] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/01/2021] [Accepted: 07/18/2021] [Indexed: 12/24/2022]
Abstract
Central respiratory chemoreceptors play a key role in the respiratory homeostasis by sensing CO2 and H+ in brain and activating the respiratory neural network. This ability of specific brain regions to respond to acidosis and hypercapnia is based on neuronal and glial mechanisms. Several decades ago, glutamatergic transmission was proposed to be involved as a main mechanism in central chemoreception. However, a complete identification of mechanism has been elusive. At the rostral medulla, chemosensitive neurons of the retrotrapezoid nucleus (RTN) are glutamatergic and they are stimulated by ATP released by RTN astrocytes in response to hypercapnia. In addition, recent findings show that caudal medullary astrocytes in brainstem can also contribute as CO2 and H+ sensors that release D-serine and glutamate, both gliotransmitters able to activate the respiratory neural network. In this review, we describe the mammalian astrocytic glutamatergic contribution to the central respiratory chemoreception trying to trace in vertebrates the emergence of several components involved in this process.
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32
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Stone TW. Relationships and Interactions between Ionotropic Glutamate Receptors and Nicotinic Receptors in the CNS. Neuroscience 2021; 468:321-365. [PMID: 34111447 DOI: 10.1016/j.neuroscience.2021.06.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 06/03/2021] [Accepted: 06/04/2021] [Indexed: 02/07/2023]
Abstract
Although ionotropic glutamate receptors and nicotinic receptors for acetylcholine (ACh) have usually been studied separately, they are often co-localized and functionally inter-dependent. The objective of this review is to survey the evidence for interactions between the two receptor families and the mechanisms underlying them. These include the mutual regulation of subunit expression, which change the NMDA:AMPA response balance, and the existence of multi-functional receptor complexes which make it difficult to distinguish between individual receptor sites, especially in vivo. This is followed by analysis of the functional relationships between the receptors from work on transmitter release, cellular electrophysiology and aspects of behavior where these can contribute to understanding receptor interactions. It is clear that nicotinic receptors (nAChRs) on axonal terminals directly regulate the release of glutamate and other neurotransmitters, α7-nAChRs generally promoting release. Hence, α7-nAChR responses will be prevented not only by a nicotinic antagonist, but also by compounds blocking the indirectly activated glutamate receptors. This accounts for the apparent anticholinergic activity of some glutamate antagonists, including the endogenous antagonist kynurenic acid. The activation of presynaptic nAChRs is by the ambient levels of ACh released from pre-terminal synapses, varicosities and glial cells, acting as a 'volume neurotransmitter' on synaptic and extrasynaptic sites. In addition, ACh and glutamate are released as CNS co-transmitters, including 'cholinergic' synapses onto spinal Renshaw cells. It is concluded that ACh should be viewed primarily as a modulator of glutamatergic neurotransmission by regulating the release of glutamate presynaptically, and the location, subunit composition, subtype balance and sensitivity of glutamate receptors, and not primarily as a classical fast neurotransmitter. These conclusions and caveats should aid clarification of the sites of action of glutamate and nicotinic receptor ligands in the search for new centrally-acting drugs.
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Affiliation(s)
- Trevor W Stone
- The Kennedy Institute of Rheumatology, University of Oxford, Oxford OX3 7FY, UK; Institute of Neuroscience, University of Glasgow, G12 8QQ, UK.
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33
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Bowles SN, Johnson CM. Inferences of glia-mediated control in Caenorhabditis elegans. J Neurosci Res 2021; 99:1191-1206. [PMID: 33559247 PMCID: PMC8005477 DOI: 10.1002/jnr.24803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 01/12/2021] [Indexed: 12/22/2022]
Abstract
Astrocytes modulate synaptic transmission; yet, it remains unclear how glia influence complex behaviors. Here, we explore the effects of Caenorhabditis elegans astrocyte-like cephalic glia (CEPglia ) and the glia-specific bHLH transcription factor HLH-17 on mating behavior and the defecation motor program (DMP). In C. elegans, male mating has been explicitly described through the male tail circuit and is characterized by coordination of multiple independent behaviors to ensure that copulation is achieved. Furthermore, the sex-specific male mating circuitry shares similar components with the DMP, which is complex and rhythmic, and requires a fixed sequence of behaviors to be activated periodically. We found that loss of CEPglia reduced persistence in executing mating behaviors and hindered copulation, while males that lacked HLH-17 demonstrated repetitive prodding behavior that increased the time spent in mating but did not hinder copulation. During the DMP, we found that posterior body wall contractions (pBocs) and enteric muscle contractions (EMCs) were differentially affected by loss of HLH-17 or CEPglia in males and hermaphrodites. pBocs and EMCs required HLH-17 activity in both sexes, whereas loss of CEPglia alone did not affect DMP in males. Our data suggest that CEPglia mediate complex behaviors by signaling to the GABAergic DVB neuron, and that HLH-17 activity influences those discrete steps within those behaviors. Collectively, these data provide evidence of glia as a link in cooperative regulation of complex and rhythmic behavior that, in C. elegans links circuitry in the head and the tail.
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Affiliation(s)
- Stephanie N. Bowles
- Department of Biology, Georgia State University, Atlanta, GA, 30303, United States
| | - Casonya M. Johnson
- Department of Biology, Georgia State University, Atlanta, GA, 30303, United States
- Department of Biology, James Madison University, Harrisonburg, VA, 22807
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Lim D, Semyanov A, Genazzani A, Verkhratsky A. Calcium signaling in neuroglia. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 362:1-53. [PMID: 34253292 DOI: 10.1016/bs.ircmb.2021.01.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Glial cells exploit calcium (Ca2+) signals to perceive the information about the activity of the nervous tissue and the tissue environment to translate this information into an array of homeostatic, signaling and defensive reactions. Astrocytes, the best studied glial cells, use several Ca2+ signaling generation pathways that include Ca2+ entry through plasma membrane, release from endoplasmic reticulum (ER) and from mitochondria. Activation of metabotropic receptors on the plasma membrane of glial cells is coupled to an enzymatic cascade in which a second messenger, InsP3 is generated thus activating intracellular Ca2+ release channels in the ER endomembrane. Astrocytes also possess store-operated Ca2+ entry and express several ligand-gated Ca2+ channels. In vivo astrocytes generate heterogeneous Ca2+ signals, which are short and frequent in distal processes, but large and relatively rare in soma. In response to neuronal activity intracellular and inter-cellular astrocytic Ca2+ waves can be produced. Astrocytic Ca2+ signals are involved in secretion, they regulate ion transport across cell membranes, and are contributing to cell morphological plasticity. Therefore, astrocytic Ca2+ signals are linked to fundamental functions of the central nervous system ranging from synaptic transmission to behavior. In oligodendrocytes, Ca2+ signals are generated by plasmalemmal Ca2+ influx, or by release from intracellular stores, or by combination of both. Microglial cells exploit Ca2+ permeable ionotropic purinergic receptors and transient receptor potential channels as well as ER Ca2+ release. In this contribution, basic morphology of glial cells, glial Ca2+ signaling toolkit, intracellular Ca2+ signals and Ca2+-regulated functions are discussed with focus on astrocytes.
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Affiliation(s)
- Dmitry Lim
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale, Novara, Italy.
| | - Alexey Semyanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia; Faculty of Biology, Moscow State University, Moscow, Russia; Sechenov First Moscow State Medical University, Moscow, Russia
| | - Armando Genazzani
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale, Novara, Italy
| | - Alexei Verkhratsky
- Sechenov First Moscow State Medical University, Moscow, Russia; Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom; Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
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Bellot-Saez A, Stevenson R, Kékesi O, Samokhina E, Ben-Abu Y, Morley JW, Buskila Y. Neuromodulation of Astrocytic K + Clearance. Int J Mol Sci 2021; 22:ijms22052520. [PMID: 33802343 PMCID: PMC7959145 DOI: 10.3390/ijms22052520] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 02/25/2021] [Accepted: 02/25/2021] [Indexed: 12/21/2022] Open
Abstract
Potassium homeostasis is fundamental for brain function. Therefore, effective removal of excessive K+ from the synaptic cleft during neuronal activity is paramount. Astrocytes play a key role in K+ clearance from the extracellular milieu using various mechanisms, including uptake via Kir channels and the Na+-K+ ATPase, and spatial buffering through the astrocytic gap-junction coupled network. Recently we showed that alterations in the concentrations of extracellular potassium ([K+]o) or impairments of the astrocytic clearance mechanism affect the resonance and oscillatory behavior of both the individual and networks of neurons. These results indicate that astrocytes have the potential to modulate neuronal network activity, however, the cellular effectors that may affect the astrocytic K+ clearance process are still unknown. In this study, we have investigated the impact of neuromodulators, which are known to mediate changes in network oscillatory behavior, on the astrocytic clearance process. Our results suggest that while some neuromodulators (5-HT; NA) might affect astrocytic spatial buffering via gap-junctions, others (DA; Histamine) primarily affect the uptake mechanism via Kir channels. These results suggest that neuromodulators can affect network oscillatory activity through parallel activation of both neurons and astrocytes, establishing a synergistic mechanism to maximize the synchronous network activity.
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Affiliation(s)
- Alba Bellot-Saez
- School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia; (A.B.-S.); (R.S.); (O.K.); (E.S.); (J.W.M.)
| | - Rebecca Stevenson
- School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia; (A.B.-S.); (R.S.); (O.K.); (E.S.); (J.W.M.)
| | - Orsolya Kékesi
- School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia; (A.B.-S.); (R.S.); (O.K.); (E.S.); (J.W.M.)
| | - Evgeniia Samokhina
- School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia; (A.B.-S.); (R.S.); (O.K.); (E.S.); (J.W.M.)
| | - Yuval Ben-Abu
- Projects and Physics Section, Sapir Academic College, D.N. Hof Ashkelon, Sderot 79165, Israel;
| | - John W. Morley
- School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia; (A.B.-S.); (R.S.); (O.K.); (E.S.); (J.W.M.)
| | - Yossi Buskila
- School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia; (A.B.-S.); (R.S.); (O.K.); (E.S.); (J.W.M.)
- International Centre for Neuromorphic Systems, The MARCS Institute, Western Sydney University, Penrith, NSW 2751, Australia
- Correspondence: ; Tel.: +61-246203853
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Fabbri R, Saracino E, Treossi E, Zamboni R, Palermo V, Benfenati V. Graphene glial-interfaces: challenges and perspectives. NANOSCALE 2021; 13:4390-4407. [PMID: 33599662 DOI: 10.1039/d0nr07824g] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Graphene nanosheets are mechanically strong but flexible, electrically conductive and bio-compatible. Thus, due to these unique properties, they are being intensively studied as materials for the next generation of neural interfaces. Most of the literature focused on optimizing the interface between these materials and neurons. However, one of the most common causes of implant failure is the adverse inflammatory reaction of glial cells. These cells are not, as previously considered, just passive and supportive cells, but play a crucial role in the physiology and pathology of the nervous system, and in the interaction with implanted electrodes. Besides providing structural support to neurons, glia are responsible for the modulation of synaptic transmission and control of central and peripheral homeostasis. Accordingly, knowledge on the interaction between glia and biomaterials is essential to develop new implant-based therapies for the treatment of neurological disorders, such as epilepsy, brain tumours, and Alzheimer's and Parkinson's disease. This work provides an overview of the emerging literature on the interaction of graphene-based materials with glial cells, together with a complete description of the different types of glial cells and problems associated with them. We believe that this description will be important for researchers working in materials science and nanotechnology to develop new active materials to interface, measure and stimulate these cells.
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Affiliation(s)
- Roberta Fabbri
- Consiglio Nazionale delle Ricerche, Istituto per la Sintesi Organica e la Fotoreattività (CNR-ISOF), via Piero Gobetti 101, 40129 Bologna, Italy.
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37
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Gaidhani N, Tucci FC, Kem WR, Beaton G, Uteshev VV. Therapeutic efficacy of α7 ligands after acute ischaemic stroke is linked to conductive states of α7 nicotinic ACh receptors. Br J Pharmacol 2021; 178:1684-1704. [PMID: 33496352 DOI: 10.1111/bph.15392] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 12/22/2020] [Accepted: 01/21/2021] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND AND PURPOSE Targeting α7 nicotinic ACh receptors (nAChRs) in neuroinflammatory disorders including acute ischaemic stroke holds significant therapeutic promise. However, therapeutically relevant signalling mechanisms remain unidentified. Activation of neuronal α7 nAChRs triggers ionotropic signalling, but there is limited evidence for it in immunoglial tissues. The α7 ligands which are effective in reducing acute ischaemic stroke damage promote α7 ionotropic activity, suggesting a link between their therapeutic effects for treating acute ischaemic stroke and activation of α7 conductive states. EXPERIMENTAL APPROACH This hypothesis was tested using a transient middle cerebral artery occlusion (MCAO) model of acute ischaemic stroke, NS6740, a known selective non-ionotropic agonist of α7 nAChRs and 4OH-GTS-21, a partial α7 agonist. NS6740-like ligands exhibiting low efficacy/potency for ionotropic activity will be referred to as non-ionotropic agonists or "metagonists". KEY RESULTS 4OH-GTS-21, used as a positive control, significantly reduced neurological deficits and brain injury after MCAO as compared to vehicle and NS6740. By contrast, NS6740 was ineffective in identical assays and reversed the effects of 4OH-GTS-21 when these compounds were co-applied. Electrophysiological recordings from acute hippocampal slices obtained from NS6740-injected animals demonstrated its remarkable brain availability and protracted effects on α7 nAChRs as evidenced by sustained (>8 h) alterations in α7 ionotropic responsiveness. CONCLUSION AND IMPLICATIONS These results suggest that α7 ionotropic activity may be obligatory for therapeutic efficacy of α7 ligands after acute ischaemic stroke yet, highlight the potential for selective application of α7 ligands to disease states based on their mode of receptor activation.
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Affiliation(s)
- Nikhil Gaidhani
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Fabio C Tucci
- Epigen Biosciences, Inc., San Diego, California, USA
| | - William R Kem
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Graham Beaton
- Epigen Biosciences, Inc., San Diego, California, USA
| | - Victor V Uteshev
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, USA
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Dong YY, Xia M, Wang L, Cui S, Li QB, Zhang JC, Meng SS, Zhang YK, Kong QX. Spatiotemporal Expression of SphK1 and S1PR2 in the Hippocampus of Pilocarpine Rat Model and the Epileptic Foci of Temporal Lobe Epilepsy. Front Cell Dev Biol 2020; 8:800. [PMID: 33134289 PMCID: PMC7578367 DOI: 10.3389/fcell.2020.00800] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Accepted: 07/28/2020] [Indexed: 01/03/2023] Open
Abstract
Temporal lobe epilepsy (TLE) is a severe chronic neurological disease caused by abnormal discharge of neurons in the brain and seriously affect the long-term life quality of patients. Currently, new insights into the pathogenesis of TLE are urgently needed to provide more personalized and effective therapeutic strategies. Accumulating evidence suggests that sphingosine kinase 1 (SphK1)/sphingosine 1-phosphate receptor 2 (S1PR2) signaling pathway plays a pivotal role in central nervous system (CNS) diseases. However, the precise altered expression of SphK1 and S1PR2 in TLE is remaining obscure. Here, we have confirmed the expression of SphK1 and S1PR2 in the pilocarpine-induced epileptic rat hippocampus and report for the first time the expression of SphK1 and S1PR2 in the temporal cortex of TLE patients. We found an increased expression of SphK1 in the brain from both epileptic rats and TLE patients. Conversely, S1PR2 expression level was markedly decreased. We further investigated the localization of SphK1 and S1PR2 in epileptic brains. Our study showed that both SphK1 and S1PR2 co-localized with activated astrocytes and neurons. Surprisingly, we observed different subcellular localization of SphK1 and S1PR2 in epileptic brain specimens. Taken together, our study suggests that the alteration of the SphK1/S1PR2 signaling axis is closely associated with the course of TLE and provides a new target for the treatment of TLE.
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Affiliation(s)
- Yuan-Yuan Dong
- Department of Neurology, Affiliated Hospital of Jining Medical University, Jining, China
| | - Min Xia
- Department of Neurology, Affiliated Hospital of Jining Medical University, Jining, China
| | - Lin Wang
- Department of Neurology, Affiliated Hospital of Jining Medical University, Jining, China
| | - Shuai Cui
- Department of Surgery, Weifang Medical University, Weifang, China
| | - Qiu-Bo Li
- Department of Pediatrics, Affiliated Hospital of Jining Medical University, Jining, China
| | - Jun-Chen Zhang
- Department of Neurosurgery, Affiliated Hospital of Jining Medical University, Jining, China
| | - Shu-Shu Meng
- Qingdao West Coast New Area Central Hospital, Qingdao, China
| | - Yan-Ke Zhang
- Department of Neurology, Affiliated Hospital of Jining Medical University, Jining, China
| | - Qing-Xia Kong
- Department of Neurology, Affiliated Hospital of Jining Medical University, Jining, China
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Gamage R, Wagnon I, Rossetti I, Childs R, Niedermayer G, Chesworth R, Gyengesi E. Cholinergic Modulation of Glial Function During Aging and Chronic Neuroinflammation. Front Cell Neurosci 2020; 14:577912. [PMID: 33192323 PMCID: PMC7594524 DOI: 10.3389/fncel.2020.577912] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 09/07/2020] [Indexed: 12/12/2022] Open
Abstract
Aging is a complex biological process that increases the risk of age-related cognitive degenerative diseases such as dementia, including Alzheimer’s disease (AD), Lewy Body Dementia (LBD), and mild cognitive impairment (MCI). Even non-pathological aging of the brain can involve chronic oxidative and inflammatory stress, which disrupts the communication and balance between the brain and the immune system. There has been an increasingly strong connection found between chronic neuroinflammation and impaired memory, especially in AD. While microglia and astrocytes, the resident immune cells of the central nervous system (CNS), exerting beneficial effects during the acute inflammatory phase, during chronic neuroinflammation they can become more detrimental. Central cholinergic circuits are involved in maintaining normal cognitive function and regulating signaling within the entire cerebral cortex. While neuronal-glial cholinergic signaling is anti-inflammatory and anti-oxidative, central cholinergic neuronal degeneration is implicated in impaired learning, memory sleep regulation, and attention. Although there is evidence of cholinergic involvement in memory, fewer studies have linked the cholinergic anti-inflammatory and anti-oxidant pathways to memory processes during development, normal aging, and disease states. This review will summarize the current knowledge of cholinergic effects on microglia and astroglia, and their role in both anti-inflammatory and anti-oxidant mechanisms, concerning normal aging and chronic neuroinflammation. We provided details on how stimulation of α7 nicotinic acetylcholine (α7nACh) receptors can be neuroprotective by increasing amyloid-β phagocytosis, decreasing inflammation and reducing oxidative stress by promoting the nuclear factor erythroid 2-related factor 2 (Nrf2) pathways and decreasing the release of pro-inflammatory cytokines. There is also evidence for astroglial α7nACh receptor stimulation mediating anti-inflammatory and antioxidant effects by inhibiting the nuclear factor-κB (NF-κB) pathway and activating the Nrf2 pathway respectively. We conclude that targeting cholinergic glial interactions between neurons and glial cells via α7nACh receptors could regulate neuroinflammation and oxidative stress, relevant to the treatment of several neurodegenerative diseases.
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Affiliation(s)
- Rashmi Gamage
- Department of Pharmacology, School of Medicine, Western Sydney University, Penrith, NSW, Australia
| | - Ingrid Wagnon
- Department of Pharmacology, School of Medicine, Western Sydney University, Penrith, NSW, Australia
| | - Ilaria Rossetti
- Department of Pharmacology, School of Medicine, Western Sydney University, Penrith, NSW, Australia
| | - Ryan Childs
- Department of Pharmacology, School of Medicine, Western Sydney University, Penrith, NSW, Australia
| | - Garry Niedermayer
- School of Science, Western Sydney University, Penrith, NSW, Australia
| | - Rose Chesworth
- School of Medicine, Western Sydney University, Penrith, NSW, Australia
| | - Erika Gyengesi
- Department of Pharmacology, School of Medicine, Western Sydney University, Penrith, NSW, Australia
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40
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Dashniani MG, Burjanadze MA, Chkhikvishvili NC, Solomonia RO, Kandashvili M, Naneishvili TL, Beselia GV, Kruashvili LB, Chighladze MR. Modulation of spatial memory and expression of hippocampal neurotransmitter receptors by selective lesion of medial septal cholinergic and GABAergic neurons. Exp Brain Res 2020; 238:2385-2397. [PMID: 32770352 DOI: 10.1007/s00221-020-05889-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 07/20/2020] [Indexed: 11/30/2022]
Abstract
The medial septum (MS) is an important modulator of hippocampal function. The degree of damage in which the particular set of septo-hippocampal projections contributes to the deficits of spatial memory with concomitant changes of hippocampal receptors expression has not been studied till present. Therefore, we investigated spatial memory and the expression level of cholinergic (α7 nACh and M1), GABAergic (α1 subunit of GABAA) and glutamatergic (NR2B subunit of NMDA and GluR 1 subunit of AMPA) receptors in the hippocampus following selective lesions of cholinergic and GABAergic septo-hippocampal projection. Learning process and long-term spatial memory were assessed using a Morris water maze. The obtained results revealed that in contrast to cholinergic lesions, rats with MS GABAergic lesions exhibit a retention deficit in 3 days after training. Western blot analyses revealed the MS cholinergic lesions have significant effect on the expression level of the M1 mACh receptors, while MS GABAergic lesions induce dramatic modulations of hippocampal glutamatergic, cholinergic and GABAergic receptors expression. These results for the first time demonstrated that selective lesions of MS cholinergic and GABAergic neurons differentially affect long-term spatial memory and the memory deficit after MS GABAergic lesion is paralleled with significant changes of hippocampal glutamate, GABA and acetylcholine receptors expression.
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Affiliation(s)
- Manana G Dashniani
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia.
| | - Maia A Burjanadze
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia
| | - Nino C Chkhikvishvili
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia
| | - Revaz O Solomonia
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia
- Institute of Chemical Biology, Ilia State University, 0162, Tbilisi, Georgia
| | - Manana Kandashvili
- Institute of Chemical Biology, Ilia State University, 0162, Tbilisi, Georgia
| | - Temur L Naneishvili
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia
| | - Gela V Beselia
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia
- Department of Physiology and Pharmacology, Petre Shotadze Tbilisi Medical Academy, 0144, Tbilisi, Georgia
| | - Lali B Kruashvili
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia
| | - Mariam R Chighladze
- Department of Behavior and Cognitive Function, I. Beritashvili Center of Experimental Biomedicine, 0160, Tbilisi, Georgia
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41
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Okubo Y. Astrocytic Ca2+ signaling mediated by the endoplasmic reticulum in health and disease. J Pharmacol Sci 2020; 144:83-88. [DOI: 10.1016/j.jphs.2020.07.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 07/07/2020] [Accepted: 07/08/2020] [Indexed: 12/19/2022] Open
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42
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Herreras O, Makarova J. Mechanisms of the negative potential associated with Leão's spreading depolarization: A history of brain electrogenesis. J Cereb Blood Flow Metab 2020; 40:1934-1952. [PMID: 32580670 PMCID: PMC7786845 DOI: 10.1177/0271678x20935998] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 05/04/2020] [Accepted: 05/18/2020] [Indexed: 12/16/2022]
Abstract
Spreading depolarization (SD) is a self-propagated wave that provokes transient disorder of numerous cell and tissue functions, and that may kill neurons in metabolically compromised tissue. We examined the mechanisms underlying the main hallmark of SD, a giant extracellular potential (ΔVo) for which multiple electromotive forces have been proposed. The end-point is that neurons and not glia, dendritic channels and not spatial currents, and increased sodium conductance rather than potassium gradients, appear to be the main actors in the generation of the negative ΔVo. Neuronal currents are established by two mechanisms, a voltage independent dendritic current, and the differential polarization along the neuron membranes. Notably, despite of a marked drop of ion gradients, these evolve significantly during SD, and yet the membrane potential remains clamped at zero no matter how much inward current is present. There may be substantial inward current or none in function of the evolving portion of the neuron dendrites with SD-activated channels. We propose that the ΔVo promotes swelling-induced dendritic damage. Understanding SD electrogenesis requires all elements relevant for membrane potential, action currents, field potentials and volume conduction to be jointly considered, and it has already encouraged the search for new targets to limit SD-related pathology.
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Affiliation(s)
- Oscar Herreras
- Department of Translational Neuroscience, Cajal Institute – CSIC, Madrid, Spain
| | - Julia Makarova
- Department of Translational Neuroscience, Cajal Institute – CSIC, Madrid, Spain
- Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
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43
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Bojarskaite L, Bjørnstad DM, Pettersen KH, Cunen C, Hermansen GH, Åbjørsbråten KS, Chambers AR, Sprengel R, Vervaeke K, Tang W, Enger R, Nagelhus EA. Astrocytic Ca 2+ signaling is reduced during sleep and is involved in the regulation of slow wave sleep. Nat Commun 2020; 11:3240. [PMID: 32632168 PMCID: PMC7338360 DOI: 10.1038/s41467-020-17062-2] [Citation(s) in RCA: 103] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 06/09/2020] [Indexed: 12/31/2022] Open
Abstract
Astrocytic Ca2+ signaling has been intensively studied in health and disease but has not been quantified during natural sleep. Here, we employ an activity-based algorithm to assess astrocytic Ca2+ signals in the neocortex of awake and naturally sleeping mice while monitoring neuronal Ca2+ activity, brain rhythms and behavior. We show that astrocytic Ca2+ signals exhibit distinct features across the sleep-wake cycle and are reduced during sleep compared to wakefulness. Moreover, an increase in astrocytic Ca2+ signaling precedes transitions from slow wave sleep to wakefulness, with a peak upon awakening exceeding the levels during whisking and locomotion. Finally, genetic ablation of an important astrocytic Ca2+ signaling pathway impairs slow wave sleep and results in an increased number of microarousals, abnormal brain rhythms, and an increased frequency of slow wave sleep state transitions and sleep spindles. Our findings demonstrate an essential role for astrocytic Ca2+ signaling in regulating slow wave sleep.
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Affiliation(s)
- Laura Bojarskaite
- Letten Centre and GliaLab, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317, Oslo, Norway
| | - Daniel M Bjørnstad
- Letten Centre and GliaLab, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317, Oslo, Norway
| | - Klas H Pettersen
- Letten Centre and GliaLab, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317, Oslo, Norway
| | - Céline Cunen
- Statistics and Data Science group, Department of Mathematics, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316, Oslo, Norway
| | - Gudmund Horn Hermansen
- Statistics and Data Science group, Department of Mathematics, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316, Oslo, Norway
| | - Knut Sindre Åbjørsbråten
- Letten Centre and GliaLab, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317, Oslo, Norway
| | - Anna R Chambers
- Lab for Neural Computation, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317, Oslo, Norway
| | - Rolf Sprengel
- Research Group of the Max Planck Institute for Medical Research, Institute for Anatomy and Cell Biology, Heidelberg University, 69120, Heidelberg, Germany
| | - Koen Vervaeke
- Lab for Neural Computation, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317, Oslo, Norway
| | - Wannan Tang
- Letten Centre and GliaLab, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317, Oslo, Norway
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Rune Enger
- Letten Centre and GliaLab, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317, Oslo, Norway.
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317, Oslo, Norway.
- Department of Neurology, Oslo University Hospital, Rikshospitalet, 0027, Oslo, Norway.
| | - Erlend A Nagelhus
- Letten Centre and GliaLab, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317, Oslo, Norway
- Department of Neurology, Oslo University Hospital, Rikshospitalet, 0027, Oslo, Norway
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44
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Rogers RC, Hasser EM, Hermann GE. Thrombin action on astrocytes in the hindbrain of the rat disrupts glycemic and respiratory control. Am J Physiol Regul Integr Comp Physiol 2020; 318:R1068-R1077. [PMID: 32320636 PMCID: PMC7311679 DOI: 10.1152/ajpregu.00033.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/30/2020] [Accepted: 04/21/2020] [Indexed: 02/06/2023]
Abstract
Severe trauma can produce a postinjury "metabolic self-destruction" characterized by catabolic metabolism and hyperglycemia. The severity of the hyperglycemia is highly correlated with posttrauma morbidity and mortality. Although no mechanism has been posited to connect severe trauma with a loss of autonomic control over metabolism, traumatic injury causes other failures of autonomic function, notably, gastric stasis and ulceration ("Cushing's ulcer"), which has been connected with the generation of thrombin. Our previous studies established that proteinase-activated receptors (PAR1; "thrombin receptors") located on astrocytes in the autonomically critical nucleus of the solitary tract (NST) can modulate gastric control circuit neurons to cause gastric stasis. Hindbrain astrocytes have also been implicated as important detectors of low glucose or glucose utilization. When activated, these astrocytes communicate with hindbrain catecholamine neurons that, in turn, trigger counterregulatory responses (CRR). There may be a convergence between the effects of thrombin to derange hindbrain gastrointestinal control and the hindbrain circuitry that initiates CRR to increase glycemia in reaction to critical hypoglycemia. Our results suggest that thrombin acts within the NST to increase glycemia through an astrocyte-dependent mechanism. Blockade of purinergic gliotransmission pathways interrupted the effect of thrombin to increase glycemia. Our studies also revealed that thrombin, acting in the NST, produced a rapid, dramatic, and potentially lethal suppression of respiratory rhythm that was also a function of purinergic gliotransmission. These results suggest that the critical connection between traumatic injury and a general collapse of autonomic regulation involves thrombin action on astrocytes.
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Affiliation(s)
- Richard C Rogers
- Autonomic Neurosciences Laboratory, Pennington Biomedical Research Center, Baton Rouge, Louisiana
| | - Eileen M Hasser
- Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
| | - Gerlinda E Hermann
- Autonomic Neurosciences Laboratory, Pennington Biomedical Research Center, Baton Rouge, Louisiana
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45
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Jurisch-Yaksi N, Yaksi E, Kizil C. Radial glia in the zebrafish brain: Functional, structural, and physiological comparison with the mammalian glia. Glia 2020; 68:2451-2470. [PMID: 32476207 DOI: 10.1002/glia.23849] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 05/07/2020] [Accepted: 05/13/2020] [Indexed: 02/01/2023]
Abstract
The neuroscience community has witnessed a tremendous expansion of glia research. Glial cells are now on center stage with leading roles in the development, maturation, and physiology of brain circuits. Over the course of evolution, glia have highly diversified and include the radial glia, astroglia or astrocytes, microglia, oligodendrocytes, and ependymal cells, each having dedicated functions in the brain. The zebrafish, a small teleost fish, is no exception to this and recent evidences point to evolutionarily conserved roles for glia in the development and physiology of its nervous system. Due to its small size, transparency, and genetic amenability, the zebrafish has become an increasingly prominent animal model for brain research. It has enabled the study of neural circuits from individual cells to entire brains, with a precision unmatched in other vertebrate models. Moreover, its high neurogenic and regenerative potential has attracted a lot of attention from the research community focusing on neural stem cells and neurodegenerative diseases. Hence, studies using zebrafish have the potential to provide fundamental insights about brain development and function, and also elucidate neural and molecular mechanisms of neurological diseases. We will discuss here recent discoveries on the diverse roles of radial glia and astroglia in neurogenesis, in modulating neuronal activity and in regulating brain homeostasis at the brain barriers. By comparing insights made in various animal models, particularly mammals and zebrafish, our goal is to highlight the similarities and differences in glia biology among species, which could set new paradigms relevant to humans.
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Affiliation(s)
- Nathalie Jurisch-Yaksi
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Neurology and Clinical Neurophysiology, St Olav University Hospital, Trondheim, Norway
| | - Emre Yaksi
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Trondheim, Norway
| | - Caghan Kizil
- German Center for Neurodegenerative Diseases (DZNE), Helmholtz Association, Dresden, Germany.,Center for Molecular and Cellular Bioengineering (CMCB), TU Dresden, Dresden, Germany
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46
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Fernández de Sevilla D, Núñez A, Buño W. Muscarinic Receptors, from Synaptic Plasticity to its Role in Network Activity. Neuroscience 2020; 456:60-70. [PMID: 32278062 DOI: 10.1016/j.neuroscience.2020.04.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 03/27/2020] [Accepted: 04/01/2020] [Indexed: 12/13/2022]
Abstract
Acetylcholine acting via metabotropic receptors plays a key role in learning and memory by regulating synaptic plasticity and circuit activity. However, a recent overall view of the effects of muscarinic acetylcholine receptors (mAChRs) on excitatory and inhibitory long-term synaptic plasticity and on circuit activity is lacking. This review focusses on specific aspects of the regulation of synaptic plasticity and circuit activity by mAChRs in the hippocampus and cortex. Acetylcholine increases the excitability of pyramidal neurons, facilitating the generation of dendritic Ca2+-spikes, NMDA-spikes and action potential bursts which provide the main source of Ca2+ influx necessary to induce synaptic plasticity. The activation of mAChRs induced Ca2+ release from intracellular IP3-sensitive stores is a major player in the induction of a NMDA independent long-term potentiation (LTP) caused by an increased expression of AMPA receptors in hippocampal pyramidal neuron dendritic spines. In the neocortex, activation of mAChRs also induces a long-term enhancement of excitatory postsynaptic currents. In addition to effects on excitatory synapses, a single brief activation of mAChRs together with short repeated membrane depolarization can induce a long-term enhancement of GABA A type (GABAA) inhibition through an increased expression of GABAA receptors in hippocampal pyramidal neurons. By contrast, a long term depression of GABAA inhibition (iLTD) is induced by muscarinic receptor activation in the absence of postsynaptic depolarizations. This iLTD is caused by an endocannabinoid-mediated presynaptic inhibition that reduces the GABA release probability at the terminals of inhibitory interneurons. This bidirectional long-term plasticity of inhibition may dynamically regulate the excitatory/inhibitory balance depending on the quiescent or active state of the postsynaptic pyramidal neurons. Therefore, acetylcholine can induce varied effects on neuronal activity and circuit behavior that can enhance sensory detection and processing through the modification of circuit activity leading to learning, memory and behavior.
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Affiliation(s)
- D Fernández de Sevilla
- Departamento de Anatomía, Histología y Neurociencia, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid 28029, Spain.
| | - A Núñez
- Departamento de Anatomía, Histología y Neurociencia, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid 28029, Spain
| | - W Buño
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid 28029, Spain
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47
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Cranston AL, Wysocka A, Steczkowska M, Zadrożny M, Palasz E, Harrington CR, Theuring F, Wischik CM, Riedel G, Niewiadomska G. Cholinergic and inflammatory phenotypes in transgenic tau mouse models of Alzheimer's disease and frontotemporal lobar degeneration. Brain Commun 2020; 2:fcaa033. [PMID: 32954291 PMCID: PMC7425524 DOI: 10.1093/braincomms/fcaa033] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Revised: 01/31/2020] [Accepted: 02/03/2020] [Indexed: 01/23/2023] Open
Abstract
An early and sizeable loss of basal forebrain cholinergic neurons is a well-characterized feature associated with measurable deficits in spatial learning and cognitive impairment in patients with Alzheimer’s disease. In addition, pro-inflammatory glial cells such as astrocytes and microglia may play a key role in the neurodegenerative cascade of Alzheimer’s disease and tauopathies. We recently presented two mouse models: Line 1, expressing the truncated tau fragment identified as the core of the Alzheimer’s paired helical filament, and Line 66, expressing full-length human tau carrying a double mutation (P301S and G335D). Line 1 mice have a pathology that is akin to Alzheimer’s, whilst Line 66 resembles frontotemporal lobar degeneration. However, their cholinergic and inflammatory phenotypes remain elusive. We performed histological evaluation of choline acetyltransferase, acetylcholinesterase, p75 neurotrophin receptor, microglial ionized calcium binding adaptor molecule 1 and astrocytic glial fibrillary acidic protein in the basal forebrain, hippocampus and cortex of these models. A significant lowering of choline acetyltransferase-positive neurons and p75-positive neurons in the basal forebrain of Line 1 at 3, 6 and 9 months was observed in two independent studies, alongside a significant decrease in acetylcholinesterase staining in the cortex and hippocampus. The reductions in choline acetyltransferase positivity varied between 30% and 50% at an age when Line 1 mice show spatial learning impairments. Furthermore, an increase in microglial ionized calcium binding adaptor molecule 1 staining was observed in the basal forebrain, hippocampus and entorhinal cortex of Line 1 at 6 months. Line 66 mice displayed an intact cholinergic basal forebrain, and no difference in p75-positive neurons at 3 or 9 months. In addition, Line 66 exhibited significant microglial ionized calcium binding adaptor molecule 1 increase in the basal forebrain and hippocampus, suggesting a prominent neuroinflammatory profile. Increased concentrations of microglial interleukin-1β and astrocytic complement 3 were also seen in the hippocampus of both Line 1 and Line 66. The cholinergic deficit in Line 1 mice confirms the Alzheimer’s disease-like phenotype in Line 1 mice, whilst Line 66 revealed no measurable change in total cholinergic expression, a phenotypic trait of frontotemporal lobar degeneration. These two transgenic lines are therefore suitable for discriminating mechanistic underpinnings between the Alzheimer’s and frontotemporal lobar degeneration-like phenotypes of these mice.
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Affiliation(s)
- Anna L Cranston
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Adrianna Wysocka
- Nencki Institute of Experimental Biology, Polish Academy of Science, Warsaw 02-093, Poland
| | | | | | - Ewelina Palasz
- Mossakowski Medical Research Centre, Warsaw 02-106, Poland
| | - Charles R Harrington
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK.,TauRx Therapeutics Ltd, Foresterhill, Aberdeen AB25 2ZP, UK
| | - Franz Theuring
- Institute of Pharmacology, Charite-Universitätsmedizin Berlin, Berlin, Germany
| | - Claude M Wischik
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK.,TauRx Therapeutics Ltd, Aberdeen AB24 5RP, UK
| | - Gernot Riedel
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Grazyna Niewiadomska
- Nencki Institute of Experimental Biology, Polish Academy of Science, Warsaw 02-093, Poland
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48
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Kofuji P, Araque A. G-Protein-Coupled Receptors in Astrocyte-Neuron Communication. Neuroscience 2020; 456:71-84. [PMID: 32224231 DOI: 10.1016/j.neuroscience.2020.03.025] [Citation(s) in RCA: 119] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/13/2020] [Accepted: 03/18/2020] [Indexed: 12/11/2022]
Abstract
Astrocytes, a major type of glial cell, are known to play key supportive roles in brain function, contributing to ion and neurotransmitter homeostasis, maintaining the blood-brain barrier and providing trophic and metabolic support for neurons. Besides these support functions, astrocytes are emerging as important elements in brain physiology through signaling exchange with neurons at tripartite synapses. Astrocytes express a wide variety of neurotransmitter transporters and receptors that allow them to sense and respond to synaptic activity. Principal among them are the G-protein-coupled receptors (GPCRs) in astrocytes because their activation by synaptically released neurotransmitters leads to mobilization of intracellular calcium. In turn, activated astrocytes release neuroactive substances called gliotransmitters, such as glutamate, GABA, and ATP/adenosine that lead to synaptic regulation through activation of neuronal GPCRs. In this review we will present and discuss recent evidence demonstrating the critical roles played by GPCRs in the bidirectional astrocyte-neuron signaling, and their crucial involvement in the astrocyte-mediated regulation of synaptic transmission and plasticity.
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Affiliation(s)
- Paulo Kofuji
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Alfonso Araque
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA.
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49
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Gonzalez A. Antioxidants and Neuron-Astrocyte Interplay in Brain Physiology: Melatonin, a Neighbor to Rely on. Neurochem Res 2020; 46:34-50. [PMID: 31989469 DOI: 10.1007/s11064-020-02972-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 01/19/2020] [Accepted: 01/21/2020] [Indexed: 12/19/2022]
Abstract
This manuscript is a review focused onto the role of astrocytes in the protection of neurons against oxidative stress and how melatonin can contribute to the maintenance of brain homeostasis. The first part of the review is dedicated to the dependence of neurons on astrocytes by terms of survival under oxidative stress conditions. Additionally, the effects of melatonin against oxidative stress in the brain and its putative role in the protection against diseases affecting the brain are highlighted. The effects of melatonin on the physiology of neurons and astrocytes also are reviewed.
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Affiliation(s)
- Antonio Gonzalez
- Department of Physiology, Institute of Molecular Pathology Biomarkers, University of Extremadura, Avenida de las Ciencias s/n, 10003, Cáceres, Spain.
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50
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Verkhratsky A, Parpura V, Vardjan N, Zorec R. Physiology of Astroglia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1175:45-91. [PMID: 31583584 DOI: 10.1007/978-981-13-9913-8_3] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Astrocytes are principal cells responsible for maintaining the brain homeostasis. Additionally, these glial cells are also involved in homocellular (astrocyte-astrocyte) and heterocellular (astrocyte-other cell types) signalling and metabolism. These astroglial functions require an expression of the assortment of molecules, be that transporters or pumps, to maintain ion concentration gradients across the plasmalemma and the membrane of the endoplasmic reticulum. Astrocytes sense and balance their neurochemical environment via variety of transmitter receptors and transporters. As they are electrically non-excitable, astrocytes display intracellular calcium and sodium fluctuations, which are not only used for operative signalling but can also affect metabolism. In this chapter we discuss the molecules that achieve ionic gradients and underlie astrocyte signalling.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK. .,Faculty of Health and Medical Sciences, Center for Basic and Translational Neuroscience, University of Copenhagen, 2200, Copenhagen, Denmark. .,Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain.
| | - Vladimir Parpura
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Nina Vardjan
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia.,Celica Biomedical, Ljubljana, Slovenia
| | - Robert Zorec
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia.,Celica Biomedical, Ljubljana, Slovenia
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