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Xu H, Li H, Zhang P, Gao Y, Ma H, Gao T, Liu H, Hua W, Zhang L, Zhang X, Yang P, Liu J. The functions of exosomes targeting astrocytes and astrocyte-derived exosomes targeting other cell types. Neural Regen Res 2024; 19:1947-1953. [PMID: 38227520 DOI: 10.4103/1673-5374.390961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Accepted: 09/08/2023] [Indexed: 01/17/2024] Open
Abstract
Astrocytes are the most abundant glial cells in the central nervous system; they participate in crucial biological processes, maintain brain structure, and regulate nervous system function. Exosomes are cell-derived extracellular vesicles containing various bioactive molecules including proteins, peptides, nucleotides, and lipids secreted from their cellular sources. Increasing evidence shows that exosomes participate in a communication network in the nervous system, in which astrocyte-derived exosomes play important roles. In this review, we have summarized the effects of exosomes targeting astrocytes and the astrocyte-derived exosomes targeting other cell types in the central nervous system. We also discuss the potential research directions of the exosome-based communication network in the nervous system. The exosome-based intercellular communication focused on astrocytes is of great significance to the biological and/or pathological processes in different conditions in the brain. New strategies may be developed for the diagnosis and treatment of neurological disorders by focusing on astrocytes as the central cells and utilizing exosomes as communication mediators.
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Affiliation(s)
- Hongye Xu
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
| | - He Li
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
- Department of Emergency, Naval Hospital of Eastern Theater, Zhoushan, Zhejiang Province, China
| | - Ping Zhang
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Yuan Gao
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Hongyu Ma
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Tianxiang Gao
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Hanchen Liu
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Weilong Hua
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Lei Zhang
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Xiaoxi Zhang
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Pengfei Yang
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Jianmin Liu
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
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2
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Xia M, Anderson TL, Prantzalos ER, Hawkinson TR, Clarke HA, Keohane SB, Sun RC, Turner JR, Ortinski PI. Voltage-gated potassium channels control extended access cocaine seeking: a role for nucleus accumbens astrocytes. Neuropsychopharmacology 2024; 49:551-560. [PMID: 37660129 PMCID: PMC10789875 DOI: 10.1038/s41386-023-01718-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 08/03/2023] [Accepted: 08/21/2023] [Indexed: 09/04/2023]
Abstract
Dopaminergic signaling in the nucleus accumbens shell (NAc) regulates neuronal activity relevant to reward-related learning, including cocaine-associated behaviors. Although astrocytes respond to dopamine and cocaine with structural changes, the impact of dopamine and cocaine on astrocyte functional plasticity has not been widely studied. Specifically, behavioral implications of voltage-gated channel activity in the canonically non-excitable astrocytes are not known. We characterized potassium channel function in NAc astrocytes following exposure to exogenous dopamine or cocaine self-administration training under short (2 h/day) and extended (6 h/day) access schedules. Electrophysiological, Ca2+ imaging, mRNA, and mass spectrometry tools were used for molecular characterization. Behavioral effects were examined after NAc-targeted microinjections of channel antagonists and astroglial toxins. Exogenous dopamine increased activity of currents mediated by voltage-gated (Kv7) channels in NAc astrocytes. This was associated with a ~5-fold increase in expression of Kcnq2 transcript level in homogenized NAc micropunches. Matrix-assisted laser desorption/ionization mass spectrometry revealed increased NAc dopamine levels in extended access, relative to short access, rats. Kv7 inhibition selectively increased frequency and amplitude of astrocyte intracellular Ca2+ transients in NAc of extended access rats. Inhibition of Kv7 channels in the NAc attenuated cocaine-seeking in extended access rats only, an effect that was occluded by microinjection of the astrocyte metabolic poison, fluorocitrate. These results suggest that voltage-gated K+ channel signaling in NAc astrocytes is behaviorally relevant, support Kv7-mediated regulation of astrocyte Ca2+ signals, and propose novel mechanisms of neuroglial interactions relevant to drug use.
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Affiliation(s)
- Mengfan Xia
- Department of Neuroscience, University of Kentucky, Lexington, KY, USA
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY, USA
| | - Tanner L Anderson
- Department of Neuroscience, University of Kentucky, Lexington, KY, USA
| | - Emily R Prantzalos
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY, USA
| | - Tara R Hawkinson
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, USA
| | - Harrison A Clarke
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, USA
| | - Shannon B Keohane
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, USA
| | - Ramon C Sun
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, USA
- Center for Advanced Spatial Biomolecule Research, University of Florida, Gainesville, FL, USA
| | - Jill R Turner
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY, USA
| | - Pavel I Ortinski
- Department of Neuroscience, University of Kentucky, Lexington, KY, USA.
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3
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Szpakowski P, Ksiazek-Winiarek D, Czpakowska J, Kaluza M, Milewska-Jedrzejczak M, Glabinski A. Astrocyte-Derived Exosomes Differentially Shape T Cells' Immune Response in MS Patients. Int J Mol Sci 2023; 24:ijms24087470. [PMID: 37108633 PMCID: PMC10138532 DOI: 10.3390/ijms24087470] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Revised: 04/07/2023] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
Astrocytes, the most abundant group of glia cells in the brain, provide support for neurons and indicate multiple various functions in the central nervous system (CNS). Growing data additionally describe their role in the regulation of immune system activity. They exert their function not only by direct contact with other cell types, but also through an indirect method, e.g., by secreting various molecules. One such structure is extracellular vesicles, which are important mediators of crosstalk between cells. In our study, we observed that the impact of exosomes derived from astrocytes with various functional phenotype differently affect the immune response of CD4+ T cells, both from healthy individuals and from patients with multiple sclerosis (MS). Astrocytes, by modulating exosome cargo, impacts the release of IFN-γ, IL-17A and CCL2 in our experimental conditions. Considering the proteins concentration in cell culture supernatants and the cellular percentage of Th phenotypes, it could be stated that human astrocytes, by the release of exosomes, are able to modify the activity of human T cells.
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Affiliation(s)
- Piotr Szpakowski
- Department of Neurology and Stroke, Medical University of Lodz, Zeromskiego 113 Street, 90-549 Lodz, Poland
| | - Dominika Ksiazek-Winiarek
- Department of Neurology and Stroke, Medical University of Lodz, Zeromskiego 113 Street, 90-549 Lodz, Poland
| | - Joanna Czpakowska
- Department of Neurology and Stroke, Medical University of Lodz, Zeromskiego 113 Street, 90-549 Lodz, Poland
| | - Mateusz Kaluza
- Department of Neurology and Stroke, Medical University of Lodz, Zeromskiego 113 Street, 90-549 Lodz, Poland
| | - Marta Milewska-Jedrzejczak
- Department of Neurology and Stroke, Medical University of Lodz, Zeromskiego 113 Street, 90-549 Lodz, Poland
| | - Andrzej Glabinski
- Department of Neurology and Stroke, Medical University of Lodz, Zeromskiego 113 Street, 90-549 Lodz, Poland
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4
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Wang L, Graziano B, Encalada N, Fernandez-Abascal J, Kaplan DH, Bianchi L. Glial regulators of ions and solutes required for specific chemosensory functions in Caenorhabditis elegans. iScience 2022; 25:105684. [PMID: 36567707 PMCID: PMC9772852 DOI: 10.1016/j.isci.2022.105684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 09/11/2022] [Accepted: 11/24/2022] [Indexed: 12/03/2022] Open
Abstract
Glia and accessory cells regulate the microenvironment around neurons and primary sensory cells. However, the impact of specific glial regulators of ions and solutes on functionally diverse primary cells is poorly understood. Here, we systemically investigate the requirement of ion channels and transporters enriched in Caenorhabditis elegans Amsh glia for the function of chemosensory neurons. Although Amsh glia ablated worms show reduced function of ASH, AWC, AWA, and ASE neurons, we show that the loss of glial enriched ion channels and transporters impacts these neurons differently, with nociceptor ASH being the most affected. Furthermore, our analysis underscores the importance of K+, Cl-, and nucleoside homeostasis in the Amphid sensory organ and uncovers the contribution of glial genes implicated in neurological disorders. Our findings build a unique fingerprint of each glial enriched ion channel and transporter and may provide insights into the function of supporting cells of mammalian sensory organs.
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Affiliation(s)
- Lei Wang
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Rm 5133 Rosenstiel Building, 1600 NW 10 Avenue, Miami, FL33136, USA
| | - Bianca Graziano
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Rm 5133 Rosenstiel Building, 1600 NW 10 Avenue, Miami, FL33136, USA
| | - Nicole Encalada
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Rm 5133 Rosenstiel Building, 1600 NW 10 Avenue, Miami, FL33136, USA
| | - Jesus Fernandez-Abascal
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Rm 5133 Rosenstiel Building, 1600 NW 10 Avenue, Miami, FL33136, USA
| | - Daryn H. Kaplan
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Rm 5133 Rosenstiel Building, 1600 NW 10 Avenue, Miami, FL33136, USA
| | - Laura Bianchi
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Rm 5133 Rosenstiel Building, 1600 NW 10 Avenue, Miami, FL33136, USA
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5
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Role of Microglia and Astrocytes in Alzheimer’s Disease: From Neuroinflammation to Ca2+ Homeostasis Dysregulation. Cells 2022; 11:cells11172728. [PMID: 36078138 PMCID: PMC9454513 DOI: 10.3390/cells11172728] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 08/26/2022] [Accepted: 08/30/2022] [Indexed: 12/12/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common form of dementia worldwide, with a complex, poorly understood pathogenesis. Cerebral atrophy, amyloid-β (Aβ) plaques, and neurofibrillary tangles represent the main pathological hallmarks of the AD brain. Recently, neuroinflammation has been recognized as a prominent feature of the AD brain and substantial evidence suggests that the inflammatory response modulates disease progression. Additionally, dysregulation of calcium (Ca2+) homeostasis represents another early factor involved in the AD pathogenesis, as intracellular Ca2+ concentration is essential to ensure proper cellular and neuronal functions. Although growing evidence supports the involvement of Ca2+ in the mechanisms of neurodegeneration-related inflammatory processes, scant data are available on its contribution in microglia and astrocytes functioning, both in health and throughout the AD continuum. Nevertheless, AD-related aberrant Ca2+ signalling in astrocytes and microglia is crucially involved in the mechanisms underpinning neuroinflammatory processes that, in turn, impact neuronal Ca2+ homeostasis and brain function. In this light, we attempted to provide an overview of the current understanding of the interactions between the glia cells-mediated inflammatory responses and the molecular mechanisms involved in Ca2+ homeostasis dysregulation in AD.
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6
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Systemic, Intrathecal, and Intracerebroventricular Antihyperalgesic Effects of the Calcium Channel Blocker CTK 01512–2 Toxin in Persistent Pain Models. Mol Neurobiol 2022; 59:4436-4452. [DOI: 10.1007/s12035-022-02864-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 04/28/2022] [Indexed: 11/25/2022]
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7
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da Silva JF, Binda NS, Pereira EMR, de Lavor MSL, Vieira LB, de Souza AH, Rigo FK, Ferrer HT, de Castro CJ, Ferreira J, Gomez MV. Analgesic effects of Phα1β toxin: a review of mechanisms of action involving pain pathways. J Venom Anim Toxins Incl Trop Dis 2021; 27:e20210001. [PMID: 34868281 PMCID: PMC8610172 DOI: 10.1590/1678-9199-jvatitd-2021-0001] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Accepted: 03/26/2021] [Indexed: 01/01/2023] Open
Abstract
Phα1β is a neurotoxin purified from spider venom that acts as a high-voltage-activated (HVA) calcium channel blocker. This spider peptide has shown a high selectivity for N-type HVA calcium channels (NVACC) and an analgesic effect in several animal models of pain. Its activity was associated with a reduction in calcium transients, glutamate release, and reactive oxygen species production from the spinal cord tissue and dorsal ganglia root (DRG) in rats and mice. It has been reported that intrathecal (i.t.) administration of Phα1β to treat chronic pain reverted opioid tolerance with a safer profile than ω-conotoxin MVIIA, a highly selective NVACC blocker. Following a recent development of recombinant Phα1β (CTK 01512-2), a new molecular target, TRPA1, the structural arrangement of disulphide bridges, and an effect on glial plasticity have been identified. CTK 01512-2 reproduced the antinociceptive effects of the native toxin not only after the intrathecal but also after the intravenous administration. Herein, we review the Phα1β antinociceptive activity in the most relevant pain models and its mechanisms of action, highlighting the impact of CTK 01512-2 synthesis and its potential for multimodal analgesia.
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Affiliation(s)
- Juliana Figueira da Silva
- Laboratory of Pharmacology, Department of Pharmacy, Federal
University of Ouro Preto, Ouro Preto, MG, Brazil
| | - Nancy Scardua Binda
- Laboratory of Pharmacology, Department of Pharmacy, Federal
University of Ouro Preto, Ouro Preto, MG, Brazil
| | - Elizete Maria Rita Pereira
- Graduate Program in Health Sciences, Institute of Education and
Research, Santa Casa de Belo Horizonte, Belo Horizonte, MG, Brazil
| | | | - Luciene Bruno Vieira
- Department of Pharmacology, Institute of Biological Sciences (ICB),
Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Alessandra Hubner de Souza
- Graduate Program in Health Sciences, Institute of Education and
Research, Santa Casa de Belo Horizonte, Belo Horizonte, MG, Brazil
| | - Flávia Karine Rigo
- Graduate Program in Health Sciences, University of the Extreme South
of Santa Catarina (UNESC), Criciúma, SC, Brazil
| | - Hèlia Tenza Ferrer
- Center of Technology in Molecular Medicine, School of Medicine,
Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Célio José de Castro
- Graduate Program in Health Sciences, Institute of Education and
Research, Santa Casa de Belo Horizonte, Belo Horizonte, MG, Brazil
| | - Juliano Ferreira
- Department of Pharmacology, Federal University of Santa Catarina,
Florianópolis, SC, Brazil
| | - Marcus Vinicius Gomez
- Graduate Program in Health Sciences, Institute of Education and
Research, Santa Casa de Belo Horizonte, Belo Horizonte, MG, Brazil
- Center of Technology in Molecular Medicine, School of Medicine,
Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
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8
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Tai Y, Ico G, Low K, Liu J, Jariwala T, Garcia‐Viramontes D, Lee KH, Myung NV, Park BH, Nam J. Formation of 3D Self-Organized Neuron-Glial Interface Derived from Neural Stem Cells via Mechano-Electrical Stimulation. Adv Healthc Mater 2021; 10:e2100806. [PMID: 34219403 DOI: 10.1002/adhm.202100806] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Revised: 06/12/2021] [Indexed: 12/18/2022]
Abstract
Due to dissimilarities in genetics and metabolism, current animal models cannot accurately depict human neurological diseases. To develop patient-specific in vitro neural models, a functional material-based technology that offers multi-potent stimuli for enhanced neural tissue development is devised. An electrospun piezoelectric poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) nanofibrous scaffold is systematically optimized to maximize its piezoelectric properties while accommodating the cellular behaviors of neural stem cells. Hydro-acoustic actuation is elegantly utilized to remotely activate the piezoelectric effect of P(VDF-TrFE) scaffolds in a physiologically-safe manner for the generation of cell-relevant electric potentials. This mechano-electrical stimulation, which arose from the deflection of the scaffold and its consequent generation of electric charges on the scaffold surface under hydro-acoustic actuation, induces the multi-phenotypic differentiation of neural stem cells simultaneously toward neuronal, oligodendrocytic, and astrocytic phenotypes. As compared to the traditional biochemically-mediated differentiation, the 3D neuron-glial interface induced by the mechano-electrical stimulation results in enhanced interactions among cellular components, leading to superior neural connectivity and functionality. These results demonstrate the potential of piezoelectric material-based technology for developing functional neural tissues in vitro via effective neural stem cell modulation with multi-faceted regenerative stimuli.
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Affiliation(s)
- Youyi Tai
- Department of Bioengineering University of California Riverside Riverside CA 92521 USA
| | - Gerardo Ico
- Department of Bioengineering University of California Riverside Riverside CA 92521 USA
| | - Karen Low
- Department of Bioengineering University of California Riverside Riverside CA 92521 USA
| | - Junze Liu
- Department of Bioengineering University of California Riverside Riverside CA 92521 USA
| | - Tanvi Jariwala
- Department of Bioengineering University of California Riverside Riverside CA 92521 USA
| | | | - Kyu Hwan Lee
- Korea Institute of Materials Science 797 Changwondaero, Seongsan gu Changwon Gyeongnam 51508 South Korea
| | - Nosang V. Myung
- Department of Chemical and Biomolecular Engineering University of Notre Dame Notre Dame IN 46556 USA
| | - B. Hyle Park
- Department of Bioengineering University of California Riverside Riverside CA 92521 USA
| | - Jin Nam
- Department of Bioengineering University of California Riverside Riverside CA 92521 USA
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9
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McNeill J, Rudyk C, Hildebrand ME, Salmaso N. Ion Channels and Electrophysiological Properties of Astrocytes: Implications for Emergent Stimulation Technologies. Front Cell Neurosci 2021; 15:644126. [PMID: 34093129 PMCID: PMC8173131 DOI: 10.3389/fncel.2021.644126] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 04/26/2021] [Indexed: 12/12/2022] Open
Abstract
Astrocytes comprise a heterogeneous cell population characterized by distinct morphologies, protein expression and function. Unlike neurons, astrocytes do not generate action potentials, however, they are electrically dynamic cells with extensive electrophysiological heterogeneity and diversity. Astrocytes are hyperpolarized cells with low membrane resistance. They are heavily involved in the modulation of K+ and express an array of different voltage-dependent and voltage-independent channels to help with this ion regulation. In addition to these K+ channels, astrocytes also express several different types of Na+ channels; intracellular Na+ signaling in astrocytes has been linked to some of their functional properties. The physiological hallmark of astrocytes is their extensive intracellular Ca2+ signaling cascades, which vary at the regional, subregional, and cellular levels. In this review article, we highlight the physiological properties of astrocytes and the implications for their function and influence of network and synaptic activity. Furthermore, we discuss the implications of these differences in the context of optogenetic and DREADD experiments and consider whether these tools represent physiologically relevant techniques for the interrogation of astrocyte function.
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Affiliation(s)
- Jessica McNeill
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada
| | | | | | - Natalina Salmaso
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada
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10
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Li H, Lones L, DiAntonio A. Bidirectional regulation of glial potassium buffering - glioprotection versus neuroprotection. eLife 2021; 10:62606. [PMID: 33646119 PMCID: PMC7946421 DOI: 10.7554/elife.62606] [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: 08/30/2020] [Accepted: 02/26/2021] [Indexed: 11/13/2022] Open
Abstract
Glia modulate neuronal excitability and seizure sensitivity by maintaining potassium and water homeostasis. A salt inducible kinase 3 (SIK3)-regulated gene expression program controls the glial capacity to buffer K+ and water in Drosophila, however upstream regulatory mechanisms are unknown. Here, we identify an octopaminergic circuit linking neuronal activity to glial ion and water buffering. Under basal conditions, octopamine functions through the inhibitory octopaminergic G-protein-coupled receptor (GPCR) OctβR to upregulate glial buffering capacity, while under pathological K+ stress, octopamine signals through the stimulatory octopaminergic GPCR OAMB1 to downregulate the glial buffering program. Failure to downregulate this program leads to intracellular glia swelling and stress signaling, suggesting that turning down this pathway is glioprotective. In the eag shaker Drosophila seizure model, the SIK3-mediated buffering pathway is inactivated. Reactivation of the glial buffering program dramatically suppresses neuronal hyperactivity, seizures, and shortened life span in this mutant. These findings highlight the therapeutic potential of a glial-centric therapeutic strategy for diseases of hyperexcitability.
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Affiliation(s)
- Hailun Li
- Department of Developmental Biology, Washington University in St. Louis School of Medicine, St. Louis, United States
| | - Lorenzo Lones
- Department of Developmental Biology, Washington University in St. Louis School of Medicine, St. Louis, United States
| | - Aaron DiAntonio
- Department of Developmental Biology, Washington University in St. Louis School of Medicine, St. Louis, United States.,Needleman Center for Neurometabolism and Axonal Therapeutics, St. Louis, United States
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11
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Götz S, Bribian A, López-Mascaraque L, Götz M, Grothe B, Kunz L. Heterogeneity of astrocytes: Electrophysiological properties of juxtavascular astrocytes before and after brain injury. Glia 2020; 69:346-361. [PMID: 32809228 DOI: 10.1002/glia.23900] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 07/20/2020] [Accepted: 07/30/2020] [Indexed: 12/31/2022]
Abstract
Astrocyte heterogeneity is increasingly recognized, but still little is known about juxtavascular astrocytes with their somata directly adjacent to blood vessels, despite their importance after brain injury. As juxtavascular astrocytes originate from common progenitor cells, that is, have a clonal origin, they may intrinsically differ from other, non-juxtavascular astrocytes. To explore this, we examined the electrophysiological properties of these groups of astrocytes and the underlying ion channels. Using brain slices of BAC Aldh1l1-eGFP transgenic mice with astrocytes labeled by GFP expression, we compared juxtavascular and non-juxtavascular astrocytes in the somatosensory cortex by means of whole-cell patch-clamp recordings and immunohistochemical staining. Prior to injury, juxta- and non-juxtavascular astrocytes exhibit comparable electrophysiological properties with characteristic mostly passive conductance and a typical negative resting membrane potential. Immunohistochemical analysis of K+ channels showed that all astrocytes were Kir 4.1+ , but revealed an intriguing difference for Kv 4.3. The expression of Kv 4.3 in sibling astrocytes (non-juxtavascular, juxtavascular and pial) was dependent on their ontogenetic origin with lowest levels in juxtavascular astrocytes located in upper cortical layers. After traumatic brain injury (TBI), we found profound changes in the electrophysiological type of astrocytes with a predominance of non-passive properties and this pattern was significantly enriched in juxtavascular astrocytes. This was accompanied by pronounced down-regulation of Kir 4.1 in proliferating astrocytes, which was significantly more in juxtavascular compared to non-juxtavascular astrocytes. Taken together, TBI induces profound differences in electrophysiological properties between juxtavascular and non-juxtavascular astrocytes that might be related to the preponderance of juxtavascular astrocyte proliferation.
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Affiliation(s)
- Stefanie Götz
- Division of Neurobiology, Department of Biology II, Ludwig-Maximilians-Universitaet (LMU) Munich, Martinsried, Germany.,Graduate School of Systemic Neurosciences, Ludwig-Maximilians-Universitaet (LMU) Munich, Martinsried, Germany.,Biomedical Center (BMC), Ludwig-Maximilians-Universitaet (LMU) Munich, SyNergy - Munich Cluster for Systems Neurology, Munich, Germany
| | - Ana Bribian
- Instituto Cajal-CSIC, Molecular, Cellular and Developmental Neurobiology Department, Madrid, Spain
| | - Laura López-Mascaraque
- Instituto Cajal-CSIC, Molecular, Cellular and Developmental Neurobiology Department, Madrid, Spain
| | - Magdalena Götz
- Biomedical Center (BMC), Ludwig-Maximilians-Universitaet (LMU) Munich, SyNergy - Munich Cluster for Systems Neurology, Munich, Germany.,Physiological Genomics, Biomedical Center (BMC), Ludwig-Maximilians-Universitaet (LMU) Munich, Martinsried, Germany.,Institute of Stem Cell Research, Helmholtz Center Munich, German Research Center for Environmental Health, Martinsried, Germany
| | - Benedikt Grothe
- Division of Neurobiology, Department of Biology II, Ludwig-Maximilians-Universitaet (LMU) Munich, Martinsried, Germany.,Biomedical Center (BMC), Ludwig-Maximilians-Universitaet (LMU) Munich, SyNergy - Munich Cluster for Systems Neurology, Munich, Germany
| | - Lars Kunz
- Division of Neurobiology, Department of Biology II, Ludwig-Maximilians-Universitaet (LMU) Munich, Martinsried, Germany
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12
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Upadhya R, Zingg W, Shetty S, Shetty AK. Astrocyte-derived extracellular vesicles: Neuroreparative properties and role in the pathogenesis of neurodegenerative disorders. J Control Release 2020; 323:225-239. [PMID: 32289328 DOI: 10.1016/j.jconrel.2020.04.017] [Citation(s) in RCA: 132] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 04/08/2020] [Accepted: 04/09/2020] [Indexed: 12/11/2022]
Abstract
Extracellular vesicles (EVs) released by neural cells play an essential role in brain homeostasis and the crosstalk between neural cells and the periphery. EVs are diverse, nano-sized vesicles, which transport proteins, nucleic acids, and lipids between cells over short and long expanses and hence are proficient for modulating the target cells. EVs released from neural cells are implicated in synaptic plasticity, neuron-glia interface, neuroprotection, neuroregeneration, and the dissemination of neuropathological molecules. This review confers the various properties of EVs secreted by astrocytes and their potential role in health and disease with a focus on evolving concepts. Naïve astrocytes shed EVs containing a host of neuroprotective compounds, which include fibroblast growth factor-2, vascular endothelial growth factor, and apolipoprotein-D. Stimulated astrocytes secrete EVs with neuroprotective molecules including heat shock proteins, synapsin 1, unique microRNAs, and glutamate transporters. Well-characterized astrocyte-derived EVs (ADEVs) generated in specific culture conditions and ADEVs that are engineered to carry the desired miRNAs or proteins are likely useful for treating brain injury and neurogenerative diseases. On the other hand, in conditions such as Alzheimer's disease (AD), stroke, Parkinson's disease, Amyotrophic lateral sclerosis (ALS), and other neuroinflammatory conditions, EVs released by activated astrocytes appear to mediate or exacerbate the pathological processes. The examples include ADEVs spreading the dysregulated complement system in AD, mediating motoneuron toxicity in ALS, and stimulating peripheral leukocyte migration into the brain in inflammatory conditions. Strategies restraining the release of EVs by activated astrocytes or modulating the composition of ADEVs are likely beneficial for treating neurodegenerative diseases. Also, periodic analyses of ADEVs in the blood is useful for detecting astrocyte-specific biomarkers in different neurological conditions and for monitoring disease progression and remission with distinct therapeutic approaches.
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Affiliation(s)
- Raghavendra Upadhya
- Institute for Regenerative Medicine, Department of Molecular and Cellular Medicine, Texas A&M University College of Medicine, College Station, TX, USA
| | - Winston Zingg
- Institute for Regenerative Medicine, Department of Molecular and Cellular Medicine, Texas A&M University College of Medicine, College Station, TX, USA
| | - Siddhant Shetty
- Institute for Regenerative Medicine, Department of Molecular and Cellular Medicine, Texas A&M University College of Medicine, College Station, TX, USA
| | - Ashok K Shetty
- Institute for Regenerative Medicine, Department of Molecular and Cellular Medicine, Texas A&M University College of Medicine, College Station, TX, USA.
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13
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Wypych D, Pomorski P. Calcium Signaling in Glioma Cells: The Role of Nucleotide Receptors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1202:67-86. [PMID: 32034709 DOI: 10.1007/978-3-030-30651-9_4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Calcium signaling is probably one of the evolutionary oldest and the most common way by which the signal can be transmitted from the cell environment to the cytoplasmic calcium binding effectors. Calcium signal is fast and due to diversity of calcium binding proteins it may have a very broad effect on cell behavior. Being a crucial player in neuronal transmission it is also very important for glia physiology. It is responsible for the cross-talk between neurons and astrocytes, for microglia activation and motility. Changes in calcium signaling are also crucial for the behavior of transformed glioma cells. The present chapter summarizes molecular mechanisms of calcium signal formation present in glial cells with a strong emphasis on extracellular nucleotide-evoked signaling pathways. Some aspects of glioma C6 signaling such as the cross-talk between P2Y1 and P2Y12 nucleotide receptors in calcium signal generation will be discussed in-depth, to show complexity of machinery engaged in formation of this signal. Moreover, possible mechanisms of modulation of the calcium signal in diverse environments there will be presented herein. Finally, the possible role of calcium signal in glioma motility is also discussed. This is a very important issue, since glioma cells, contrary to the vast majority of neoplastic cells, cannot spread in the body with the bloodstream and, at least in early stages of tumor development, may expand only by means of sheer motility.
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Affiliation(s)
- Dorota Wypych
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Paweł Pomorski
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland.
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14
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Denizot A, Arizono M, Nägerl UV, Soula H, Berry H. Simulation of calcium signaling in fine astrocytic processes: Effect of spatial properties on spontaneous activity. PLoS Comput Biol 2019; 15:e1006795. [PMID: 31425510 PMCID: PMC6726244 DOI: 10.1371/journal.pcbi.1006795] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 09/04/2019] [Accepted: 07/08/2019] [Indexed: 12/20/2022] Open
Abstract
Astrocytes, a glial cell type of the central nervous system, have emerged as detectors and regulators of neuronal information processing. Astrocyte excitability resides in transient variations of free cytosolic calcium concentration over a range of temporal and spatial scales, from sub-microdomains to waves propagating throughout the cell. Despite extensive experimental approaches, it is not clear how these signals are transmitted to and integrated within an astrocyte. The localization of the main molecular actors and the geometry of the system, including the spatial organization of calcium channels IP3R, are deemed essential. However, as most calcium signals occur in astrocytic ramifications that are too fine to be resolved by conventional light microscopy, most of those spatial data are unknown and computational modeling remains the only methodology to study this issue. Here, we propose an IP3R-mediated calcium signaling model for dynamics in such small sub-cellular volumes. To account for the expected stochasticity and low copy numbers, our model is both spatially explicit and particle-based. Extensive simulations show that spontaneous calcium signals arise in the model via the interplay between excitability and stochasticity. The model reproduces the main forms of calcium signals and indicates that their frequency crucially depends on the spatial organization of the IP3R channels. Importantly, we show that two processes expressing exactly the same calcium channels can display different types of calcium signals depending on the spatial organization of the channels. Our model with realistic process volume and calcium concentrations successfully reproduces spontaneous calcium signals that we measured in calcium micro-domains with confocal microscopy and predicts that local variations of calcium indicators might contribute to the diversity of calcium signals observed in astrocytes. To our knowledge, this model is the first model suited to investigate calcium dynamics in fine astrocytic processes and to propose plausible mechanisms responsible for their variability.
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Affiliation(s)
- Audrey Denizot
- INRIA, F-69603, Villeurbanne, France
- Univ Lyon, LIRIS, UMR5205 CNRS, F-69621, Villeurbanne, France
| | - Misa Arizono
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Bordeaux, France
| | - U. Valentin Nägerl
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Bordeaux, France
| | - Hédi Soula
- INRIA, F-69603, Villeurbanne, France
- Univ P&M Curie, CRC, INSERM UMRS 1138, F-75006, Paris, France
| | - Hugues Berry
- INRIA, F-69603, Villeurbanne, France
- Univ Lyon, LIRIS, UMR5205 CNRS, F-69621, Villeurbanne, France
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15
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Tenza-Ferrer H, Magno LAV, Romano-Silva MA, da Silva JF, Gomez MV. Phα1β Spider Toxin Reverses Glial Structural Plasticity Upon Peripheral Inflammation. Front Cell Neurosci 2019; 13:306. [PMID: 31354431 PMCID: PMC6635560 DOI: 10.3389/fncel.2019.00306] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 06/24/2019] [Indexed: 01/03/2023] Open
Abstract
The incoming signals from injured sensory neurons upon peripheral inflammation are processed in the dorsal horn of spinal cord, where glial cells accumulate and play a critical role in initiating allodynia (increased pain in response to light-touch). However, how painful stimuli in the periphery engage glial reactivity in the spinal cord remains unclear. Here, we found that a hind paw inflammation induced by CFA produces robust morphological changes in spinal astrocytes and microglia compatible with the reactive phenotype. Strikingly, we discovered that a single intrathecal injection with venom peptides that inhibit calcium channels reversed all the glial pathological features of the peripheral inflammation. These effects were more apparent in rats treated with the Phα1β spider toxin (non-specific calcium channel antagonist) than ω-MVIIA cone snail toxin (selective N-type calcium channel antagonist). These data reveal for the first time a venom peptide acting on glial structural remodeling in vivo. We, therefore, suggest that calcium-dependent plasticity is an essential trigger for glial cells to initiate reactivity, which may represent a new target for the antinociceptive effects of Phα1β and ω-MVIIA toxins in inflammatory pain conditions.
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Affiliation(s)
- Helia Tenza-Ferrer
- Centro de Tecnologia em Medicina Molecular, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Luiz Alexandre Viana Magno
- Centro de Tecnologia em Medicina Molecular, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Marco Aurélio Romano-Silva
- Centro de Tecnologia em Medicina Molecular, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil.,Departamento de Saúde Mental, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Juliana Figueira da Silva
- Centro de Tecnologia em Medicina Molecular, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil.,Laboratório de Toxinas, Instituto de Ensino e Pesquisa da Santa Casa de Belo Horizonte, Belo Horizonte, Brazil
| | - Marcus Vinicius Gomez
- Centro de Tecnologia em Medicina Molecular, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil.,Laboratório de Toxinas, Instituto de Ensino e Pesquisa da Santa Casa de Belo Horizonte, Belo Horizonte, Brazil
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16
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Garcia VJ, Rushton DJ, Tom CM, Allen ND, Kemp PJ, Svendsen CN, Mattis VB. Huntington's Disease Patient-Derived Astrocytes Display Electrophysiological Impairments and Reduced Neuronal Support. Front Neurosci 2019; 13:669. [PMID: 31316341 PMCID: PMC6610155 DOI: 10.3389/fnins.2019.00669] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 06/11/2019] [Indexed: 12/03/2022] Open
Abstract
In Huntington’s disease (HD), while the ubiquitously expressed mutant Huntingtin (mtHTT) protein primarily compromises striatal and cortical neurons, glia also undergo disease-contributing alterations. Existing HD models using human induced pluripotent stem cells (iPSCs) have not extensively characterized the role of mtHTT in patient-derived astrocytes. Here physiologically mature astrocytes are generated from HD patient iPSCs. These human astrocytes exhibit hallmark HD phenotypes that occur in mouse models, including impaired inward rectifying K+ currents, lengthened spontaneous Ca2+ waves and reduced cell membrane capacitance. HD astrocytes in co-culture provided reduced support for the maturation of iPSC-derived neurons. In addition, neurons exposed to chronic glutamate stimulation are not protected by HD astrocytes. This iPSC-based HD model demonstrates the critical effects of mtHTT on human astrocytes, which not only broadens the understanding of disease susceptibility beyond cortical and striatal neurons but also increases potential drug targets.
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Affiliation(s)
- Veronica J Garcia
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - David J Rushton
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States.,Divisions of Biomedicine and Neuroscience, School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Colton M Tom
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Nicholas D Allen
- Divisions of Biomedicine and Neuroscience, School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Paul J Kemp
- Divisions of Biomedicine and Neuroscience, School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Clive N Svendsen
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Virginia B Mattis
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
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17
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Monitoring Interneuron-Astrocyte Signaling and Its Consequences on Synaptic Transmission. Methods Mol Biol 2019; 1938:117-129. [PMID: 30617977 DOI: 10.1007/978-1-4939-9068-9_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Whole-cell patch clamp allows the characterization of synaptic transmission in neurons. It is possible to manipulate astrocytic activity and record how these glial cells affect neuronal networks. Here we describe the methodology to monitor the endogenously activation of astrocytes by inhibitory synaptic activity. Afterward, such glial activation will let us study the consequences of interneuron-astrocyte signaling on excitatory neurotransmission at hippocampal synapses.
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18
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Abdel-Maksoud MS, El-Gamal MI, Benhalilou DR, Ashraf S, Mohammed SA, Oh CH. Mechanistic/mammalian target of rapamycin: Recent pathological aspects and inhibitors. Med Res Rev 2018; 39:631-664. [PMID: 30251347 DOI: 10.1002/med.21535] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 07/31/2018] [Accepted: 08/01/2018] [Indexed: 12/23/2022]
Abstract
The mechanistic/mammalian target of rapamycin (mTOR), also known as the mechanistic target of rapamycin, regulates many normal cell processes such as transcription, cell growth, and autophagy. Overstimulation of mTOR by its ligands, amino acids, sugars, and/or growth factors leads to physiological disorders, including cancer and neurodegenerative diseases. In this study, we reviewed the recent advances regarding the mechanism that involves mTOR in cancer, aging, and neurodegenerative diseases. The chemical and biological properties of recently reported small molecules that function as mTOR kinase inhibitors, including adenosine triphosphate-competitive inhibitors and dual mTOR/PI3K inhibitors, have also been reviewed. We focused on the reports published in the literature from 2012 to 2017.
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Affiliation(s)
- Mohammed S Abdel-Maksoud
- Medicinal & Pharmaceutical Chemistry Department, Pharmaceutical and Drug Industries Research Division, National Research Centre (NRC), Giza, Egypt
| | - Mohammed I El-Gamal
- Department of Medicinal Chemistry, College of Pharmacy, University of Sharjah, Sharjah, United Arab Emirates.,Department of Medicinal Chemistry, Faculty of Pharmacy, University of Mansoura, Mansoura, Egypt
| | - Dalia Reyane Benhalilou
- Department of Medicinal Chemistry, College of Pharmacy, University of Sharjah, Sharjah, United Arab Emirates
| | - Sandy Ashraf
- Department of Medicinal Chemistry, College of Pharmacy, University of Sharjah, Sharjah, United Arab Emirates
| | | | - Chang-Hyun Oh
- Center for Biomaterials, Korea Institute of Science and Technology, Seoul, Korea.,Department of Biomolecular Science, University of Science and Technology, Daejeon, Korea
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19
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Fang Y, Jiang Y, Ledesma HA, Yi J, Gao X, Weiss DE, Shi F, Tian B. Texturing Silicon Nanowires for Highly Localized Optical Modulation of Cellular Dynamics. NANO LETTERS 2018; 18:4487-4492. [PMID: 29894630 PMCID: PMC6814189 DOI: 10.1021/acs.nanolett.8b01626] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Engineered silicon-based materials can display photoelectric and photothermal responses under light illumination, which may lead to further innovations at the silicon-biology interfaces. Silicon nanowires have small radial dimensions, promising as highly localized cellular modulators, however the single crystalline form typically has limited photothermal efficacy due to the poor light absorption and fast heat dissipation. In this work, we report strategies to improve the photothermal response from silicon nanowires by introducing nanoscale textures on the surface and in the bulk. We next demonstrate high-resolution extracellular modulation of calcium dynamics in a number of mammalian cells including glial cells, neurons, and cancer cells. The new materials may be broadly used in probing and modulating electrical and chemical signals at the subcellular length scale, which is currently a challenge in the field of electrophysiology or cellular engineering.
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Affiliation(s)
- Yin Fang
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
- The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
| | - Yuanwen Jiang
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
- The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
| | - Hector Acaron Ledesma
- Graduate Program in Biophysical Sciences, The University of Chicago, Chicago, Illinois 60637, United States
| | - Jaeseok Yi
- The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
| | - Xiang Gao
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Dara E. Weiss
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Fengyuan Shi
- The Research Resources Center, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Bozhi Tian
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
- The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
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20
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Galloway A, Adeluyi A, O'Donovan B, Fisher ML, Rao CN, Critchfield P, Sajish M, Turner JR, Ortinski PI. Dopamine Triggers CTCF-Dependent Morphological and Genomic Remodeling of Astrocytes. J Neurosci 2018; 38:4846-4858. [PMID: 29712779 PMCID: PMC5966792 DOI: 10.1523/jneurosci.3349-17.2018] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 03/29/2018] [Accepted: 04/19/2018] [Indexed: 02/07/2023] Open
Abstract
Dopamine is critical for processing of reward and etiology of drug addiction. Astrocytes throughout the brain express dopamine receptors, but consequences of astrocytic dopamine receptor signaling are not well established. We found that extracellular dopamine triggered rapid concentration-dependent stellation of astrocytic processes that was not a result of dopamine oxidation but instead relied on both cAMP-dependent and cAMP-independent dopamine receptor signaling. This was accompanied by reduced duration and increased frequency of astrocytic Ca2+ transients, but little effect on astrocytic voltage-gated potassium channel currents. To isolate possible mechanisms underlying these structural and functional changes, we used whole-genome RNA sequencing and found prominent dopamine-induced enrichment of genes containing the CCCTC-binding factor (CTCF) motif, suggesting involvement of chromatin restructuring in the nucleus. CTCF binding to promoter sites bidirectionally regulates gene transcription and depends on activation of poly-ADP-ribose polymerase 1 (PARP1). Accordingly, antagonism of PARP1 occluded dopamine-induced changes, whereas a PARP1 agonist facilitated dopamine-induced changes on its own. These results indicate that astrocyte response to elevated dopamine involves PARP1-mediated CTCF genomic restructuring and concerted expression of gene networks. Our findings propose epigenetic regulation of chromatin landscape as a critical factor in the rapid astrocyte response to dopamine.SIGNIFICANCE STATEMENT Although dopamine is widely recognized for its role in modulating neuronal responses both in healthy and disease states, little is known about dopamine effects at non-neuronal cells in the brain. To address this gap, we performed whole-genome sequencing of astrocytes exposed to elevated extracellular dopamine and combined it with evaluation of effects on astrocyte morphology and function. We demonstrate a temporally dynamic pattern of genomic plasticity that triggers pronounced changes in astrocyte morphology and function. We further show that this plasticity depends on activation of genes sensitive to DNA-binding protein CTCF. Our results propose that a broad pattern of astrocyte responses to dopamine specifically relies on CTCF-dependent gene networks.
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Affiliation(s)
- Ashley Galloway
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, South Carolina 29209
- Integrated Program in Biomedical Sciences, University of South Carolina, Columbia, South Carolina 29209, and
| | - Adewale Adeluyi
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina 29208
| | - Bernadette O'Donovan
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, South Carolina 29209
| | - Miranda L Fisher
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina 29208
| | - Chintada Nageswara Rao
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina 29208
| | - Peyton Critchfield
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, South Carolina 29209
| | - Mathew Sajish
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina 29208
| | - Jill R Turner
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina 29208
| | - Pavel I Ortinski
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, South Carolina 29209,
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21
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Wu W, Yao H, Zhao HW, Wang J, Haddad GG. Down-regulation of Inwardly Rectifying K + Currents in Astrocytes Derived from Patients with Monge's Disease. Neuroscience 2018; 374:70-79. [PMID: 29355592 DOI: 10.1016/j.neuroscience.2018.01.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 01/04/2018] [Indexed: 12/25/2022]
Abstract
Chronic mountain sickness (CMS) or Monge's disease is a disease in highlanders. These patients have a variety of neurologic symptoms such as migraine, mental fatigue, confusion, dizziness, loss of appetite, memory loss and neuronal degeneration. The cellular and molecular mechanisms underlying CMS neuropathology is not understood. In the previous study, we demonstrated that neurons derived from CMS patients' fibroblasts have a decreased expression and altered gating properties of voltage-gated sodium channel. In this study, we further characterize the electrophysiological properties of iPSC-derived astrocytes from CMS patients. We found that the current densities of the inwardly rectifying potassium (Kir) channels in CMS astrocytes (-5.7 ± 2.2 pA/pF at -140 mV) were significantly decreased as compared to non-CMS (-28.4 ± 3.4 pA/pF at -140 mV) and sea level subjects (-28.3 ± 5.3 pA/pF at -140 mV). We further demonstrated that the reduced Kir current densities in CMS astrocytes were caused by their decreased protein expression of Kir4.1 and Kir2.3 channels, while single channel properties (i.e., Po, conductance) of Kir channel in CMS astrocytes were not altered. In addition, we found no significant differences of outward potassium currents between CMS and non-CMS astrocytes. As compared to non-CMS and sea level subjects, the K+ uptake ability in CMS astrocytes was significantly decreased. Taken together, our results suggest that down-regulation of Kir channels and the resulting decreased K+ uptake ability in astrocytes could be one of the major molecular mechanisms underlying the neurologic manifestations in CMS patients.
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Affiliation(s)
- Wei Wu
- Department of Pediatrics, University of California San Diego, La Jolla, CA 92093, United States
| | - Hang Yao
- Department of Pediatrics, University of California San Diego, La Jolla, CA 92093, United States
| | - Helen W Zhao
- Department of Pediatrics, University of California San Diego, La Jolla, CA 92093, United States
| | - Juan Wang
- Department of Pediatrics, University of California San Diego, La Jolla, CA 92093, United States
| | - Gabriel G Haddad
- Department of Pediatrics, University of California San Diego, La Jolla, CA 92093, United States; Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, United States; Rady Children's Hospital-San Diego, San Diego, CA 92123, United States.
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22
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Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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23
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Verkhratsky A, Nedergaard M. Physiology of Astroglia. Physiol Rev 2018; 98:239-389. [PMID: 29351512 PMCID: PMC6050349 DOI: 10.1152/physrev.00042.2016] [Citation(s) in RCA: 928] [Impact Index Per Article: 154.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/22/2017] [Accepted: 04/27/2017] [Indexed: 02/07/2023] Open
Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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24
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Mestre ALG, Inácio PMC, Elamine Y, Asgarifar S, Lourenço AS, Cristiano MLS, Aguiar P, Medeiros MCR, Araújo IM, Ventura J, Gomes HL. Extracellular Electrophysiological Measurements of Cooperative Signals in Astrocytes Populations. Front Neural Circuits 2017; 11:80. [PMID: 29109679 PMCID: PMC5660104 DOI: 10.3389/fncir.2017.00080] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 10/06/2017] [Indexed: 01/28/2023] Open
Abstract
Astrocytes are neuroglial cells that exhibit functional electrical properties sensitive to neuronal activity and capable of modulating neurotransmission. Thus, electrophysiological recordings of astroglial activity are very attractive to study the dynamics of glial signaling. This contribution reports on the use of ultra-sensitive planar electrodes combined with low noise and low frequency amplifiers that enable the detection of extracellular signals produced by primary cultures of astrocytes isolated from mouse cerebral cortex. Recorded activity is characterized by spontaneous bursts comprised of discrete signals with pronounced changes on the signal rate and amplitude. Weak and sporadic signals become synchronized and evolve with time to higher amplitude signals with a quasi-periodic behavior, revealing a cooperative signaling process. The methodology presented herewith enables the study of ionic fluctuations of population of cells, complementing the single cells observation by calcium imaging as well as by patch-clamp techniques.
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Affiliation(s)
- Ana L G Mestre
- Faculdade de Ciências e Tecnologia, Universidade do Algarve, Faro, Portugal.,Instituto de Telecomunicações, Lisboa, Portugal
| | - Pedro M C Inácio
- Faculdade de Ciências e Tecnologia, Universidade do Algarve, Faro, Portugal.,Instituto de Telecomunicações, Lisboa, Portugal
| | - Youssef Elamine
- Faculdade de Ciências e Tecnologia, Universidade do Algarve, Faro, Portugal.,Instituto de Telecomunicações, Lisboa, Portugal
| | - Sanaz Asgarifar
- Faculdade de Ciências e Tecnologia, Universidade do Algarve, Faro, Portugal.,Instituto de Telecomunicações, Lisboa, Portugal
| | - Ana S Lourenço
- Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, Faro, Portugal.,Centro de Investigação em Biomedicina, Universidade do Algarve, Faro, Portugal
| | - Maria L S Cristiano
- Faculdade de Ciências e Tecnologia, Universidade do Algarve, Faro, Portugal.,Centro de Ciências do Mar, Universidade do Algarve, Faro, Portugal
| | - Paulo Aguiar
- Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal.,Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Maria C R Medeiros
- Departamento de Engenharia Electrotécnica e de Computadores, Instituto de Telecomunicações, Universidade de Coimbra, Coimbra, Portugal
| | - Inês M Araújo
- Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, Faro, Portugal.,Centro de Investigação em Biomedicina, Universidade do Algarve, Faro, Portugal
| | - João Ventura
- Departamento de Física e Astronomia, Instituto de Física dos Materiais da Universidade do Porto, Instituto de Nanociências e Nanotecnologia, Universidade do Porto, Porto, Portugal
| | - Henrique L Gomes
- Faculdade de Ciências e Tecnologia, Universidade do Algarve, Faro, Portugal.,Instituto de Telecomunicações, Lisboa, Portugal
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Connexin 43-Mediated Astroglial Metabolic Networks Contribute to the Regulation of the Sleep-Wake Cycle. Neuron 2017; 95:1365-1380.e5. [PMID: 28867552 DOI: 10.1016/j.neuron.2017.08.022] [Citation(s) in RCA: 131] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Revised: 06/29/2017] [Accepted: 08/14/2017] [Indexed: 01/13/2023]
Abstract
Astrocytes produce and supply metabolic substrates to neurons through gap junction-mediated astroglial networks. However, the role of astroglial metabolic networks in behavior is unclear. Here, we demonstrate that perturbation of astroglial networks impairs the sleep-wake cycle. Using a conditional Cre-Lox system in mice, we show that knockout of the gap junction subunit connexin 43 in astrocytes throughout the brain causes excessive sleepiness and fragmented wakefulness during the nocturnal active phase. This astrocyte-specific genetic manipulation silenced the wake-promoting orexin neurons located in the lateral hypothalamic area (LHA) by impairing glucose and lactate trafficking through astrocytic networks. This global wakefulness instability was mimicked with viral delivery of Cre recombinase to astrocytes in the LHA and rescued by in vivo injections of lactate. Our findings propose a novel regulatory mechanism critical for maintaining normal daily cycle of wakefulness and involving astrocyte-neuron metabolic interactions.
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Pérez-Samartín A, Garay E, Moctezuma JPH, Cisneros-Mejorado A, Sánchez-Gómez MV, Martel-Gallegos G, Robles-Martínez L, Canedo-Antelo M, Matute C, Arellano RO. Inwardly Rectifying K + Currents in Cultured Oligodendrocytes from Rat Optic Nerve are Insensitive to pH. Neurochem Res 2017; 42:2443-2455. [PMID: 28345117 DOI: 10.1007/s11064-017-2242-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 03/14/2017] [Accepted: 03/17/2017] [Indexed: 10/25/2022]
Abstract
Inwardly rectifying K+ (Kir) channel expression signals at an advanced stage of maturation during oligodendroglial differentiation. Knocking down their expression halts the generation of myelin and produces severe abnormalities in the central nervous system. Kir4.1 is the main subunit involved in the tetrameric structure of Kir channels in glial cells; however, the precise composition of Kir channels expressed in oligodendrocytes (OLs) remains partially unknown, as participation of other subunits has been proposed. Kir channels are sensitive to H+; thus, intracellular acidification produces Kir current inhibition. Since Kir subunits have differential sensitivity to H+, we studied the effect of intracellular acidification on Kir currents expressed in cultured OLs derived from optic nerves of 12-day-old rats. Unexpectedly, Kir currents in OLs (2-4 DIV) did not change within the pH range of 8.0-5.0, as observed when using standard whole-cell voltage-clamp recording or when preserving cytoplasmic components with the perforated patch-clamp technique. In contrast, low pH inhibited astrocyte Kir currents, which was consistent with the involvement of the Kir4.1 subunit. The H+-insensitivity expressed in OL Kir channels was not intrinsic because Kir cloning showed no difference in the sequence reported for the Kir4.1, Kir2.1, or Kir5.1 subunits. Moreover, when Kir channels were heterologously expressed in Xenopus oocytes they behaved as expected in their general properties and sensitivity to H+. It is therefore concluded that Kir channel H+-sensitivity in OLs is modulated through an extrinsic mechanism, probably by association with a modulatory component or by posttranslational modifications.
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Affiliation(s)
- Alberto Pérez-Samartín
- Achucarro Basque Center for Neuroscience, Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas, Departamento de Neurociencias, Universidad del País Vasco, 48940, Leioa, Vizcaya, Spain
| | - Edith Garay
- Laboratorio de Neurofisiología Celular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Juriquilla, 76230, Querétaro, Mexico
| | - Juan Pablo H Moctezuma
- Laboratorio de Neurofisiología Celular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Juriquilla, 76230, Querétaro, Mexico
| | - Abraham Cisneros-Mejorado
- Laboratorio de Neurofisiología Celular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Juriquilla, 76230, Querétaro, Mexico
| | - María Victoria Sánchez-Gómez
- Achucarro Basque Center for Neuroscience, Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas, Departamento de Neurociencias, Universidad del País Vasco, 48940, Leioa, Vizcaya, Spain
| | - Guadalupe Martel-Gallegos
- Laboratorio de Neurofisiología Celular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Juriquilla, 76230, Querétaro, Mexico
| | - Leticia Robles-Martínez
- Laboratorio de Neurofisiología Celular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Juriquilla, 76230, Querétaro, Mexico
| | - Manuel Canedo-Antelo
- Achucarro Basque Center for Neuroscience, Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas, Departamento de Neurociencias, Universidad del País Vasco, 48940, Leioa, Vizcaya, Spain
| | - Carlos Matute
- Achucarro Basque Center for Neuroscience, Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas, Departamento de Neurociencias, Universidad del País Vasco, 48940, Leioa, Vizcaya, Spain.
| | - Rogelio O Arellano
- Laboratorio de Neurofisiología Celular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Juriquilla, 76230, Querétaro, Mexico.
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Ono K, Suzuki H, Yamamoto R, Sahashi H, Takido Y, Sawada M. Optogenetic control of cell differentiation in channelrhodopsin-2-expressing OS3, a bipotential glial progenitor cell line. Neurochem Int 2017; 104:49-63. [DOI: 10.1016/j.neuint.2016.12.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 12/15/2016] [Accepted: 12/15/2016] [Indexed: 01/20/2023]
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28
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Rocha PRF, Medeiros MCR, Kintzel U, Vogt J, Araújo IM, Mestre ALG, Mailänder V, Schlett P, Dröge M, Schneider L, Biscarini F, de Leeuw DM, Gomes HL. Extracellular electrical recording of pH-triggered bursts in C6 glioma cell populations. SCIENCE ADVANCES 2016; 2:e1600516. [PMID: 28028533 PMCID: PMC5182051 DOI: 10.1126/sciadv.1600516] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 11/18/2016] [Indexed: 05/29/2023]
Abstract
Glioma patients often suffer from epileptic seizures because of the tumor's impact on the brain physiology. Using the rat glioma cell line C6 as a model system, we performed long-term live recordings of the electrical activity of glioma populations in an ultrasensitive detection method. The transducer exploits large-area electrodes that maximize double-layer capacitance, thus increasing the sensitivity. This strategy allowed us to record glioma electrical activity. We show that although glioma cells are nonelectrogenic, they display a remarkable electrical burst activity in time. The low-frequency current noise after cell adhesion is dominated by the flow of Na+ ions through voltage-gated ion channels. However, after an incubation period of many hours, the current noise markedly increased. This electric bursting phenomenon was not associated with apoptosis because the cells were viable and proliferative during the period of increased electric activity. We detected a rapid cell culture medium acidification accompanying this event. By using specific inhibitors, we showed that the electrical bursting activity was prompted by extracellular pH changes, which enhanced Na+ ion flux through the psalmotoxin 1-sensitive acid-sensing ion channels. Our model of pH-triggered bursting was unambiguously supported by deliberate, external acidification of the cell culture medium. This unexpected, acidosis-driven electrical activity is likely to directly perturb, in vivo, the functionality of the healthy neuronal network in the vicinity of the tumor bulk and may contribute to seizures in glioma patients.
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Affiliation(s)
- Paulo R. F. Rocha
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
| | - Maria C. R. Medeiros
- Instituto de Telecomunicações, Departamento de Engenharia Electrotécnica e de Computadores, Universidade de Coimbra, 3030-290 Coimbra, Portugal
| | - Ulrike Kintzel
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
| | - Johannes Vogt
- Institute of Microanatomy and Neurobiology, University Medical Center Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany
| | - Inês M. Araújo
- Department of Biomedical Sciences and Medicine, University of Algarve, 8005-139 Faro, Portugal
- Centre for Biomedical Research, University of Algarve, 8005-139 Faro, Portugal
| | - Ana L. G. Mestre
- Instituto de Telecomunicações, Avenida Rovisco, Pais 1, 1049-001 Lisboa, Portugal
- Universidade do Algarve, Faculdade de Ciências e Tecnologia, 8005-139 Faro, Portugal
| | - Volker Mailänder
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
- Dermatology Clinic, University Medicine of the Johannes-Gutenberg Universität Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany
| | - Paul Schlett
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
| | - Melanie Dröge
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
| | - Leonid Schneider
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
| | - Fabio Biscarini
- Department of Life Sciences, Università di Modena e Reggio Emilia, Via Campi 103, I-41125 Modena, Italy
| | - Dago M. de Leeuw
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
- Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS, Delft, Netherlands
| | - Henrique L. Gomes
- Instituto de Telecomunicações, Avenida Rovisco, Pais 1, 1049-001 Lisboa, Portugal
- Universidade do Algarve, Faculdade de Ciências e Tecnologia, 8005-139 Faro, Portugal
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Romero DM, Berardino BG, Wolansky MJ, Kotler ML. From the Cover: Vulnerability of C6 Astrocytoma Cells After Single-Compound and Joint Exposure to Type I and Type II Pyrethroid Insecticides. Toxicol Sci 2016; 155:196-212. [PMID: 27815491 DOI: 10.1093/toxsci/kfw188] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A primary mode-of-action of all pyrethroid insecticides (PYRs) is the disruption of the voltage-gated sodium channel electrophysiology in neurons of target pests and nontarget species. The neurological actions of PYRs on non-neuronal cells of the nervous system remain poorly investigated. In the present work, we used C6 astrocytoma cells to study PYR actions (0.1-50 μM) under the hypothesis that glial cells may be targeted by and vulnerable to PYRs. To this end, we characterized the effects of bifenthrin (BF), tefluthrin (TF), α-cypermethrin (α-CYP), and deltamethrin (DM) on the integrity of nuclear, mitochondrial, and lysosomal compartments. In general, 24- to 48-h exposures produced concentration-related impairment of cell viability. In single-compound, 24-h exposure experiments, effective concentration (EC)15s 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT assay) were computed as follows (in μM): BF, 16.1; TF, 37.3; α-CYP, 7.8; DM, 5.0. We found concentration-related damage in several C6-cell subcellular compartments (mitochondria, nuclei, and lysosomes) at ≥ 10-1 μM levels. Last, we examined a mixture of all PYRs (ie, Σ individual EC15) using MTT assays and subcellular analyses. Our findings indicate that C6 cells are responsive to nM levels of PYRs, suggesting that astroglial susceptibility may contribute to the low-dose neurological effects caused by these insecticides. This research further suggests that C6 cells may provide relevant information as a screening platform for pesticide mixtures targeting nervous system cells by expected and unexpected toxicogenic pathways potentially contributing to clinical neurotoxicity.
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Affiliation(s)
- Delfina M Romero
- Laboratorio de Toxicología de Mezclas Químicas.,Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina.,IQUIBICEN-Argentina National Research Council (CONICET)
| | - Bruno G Berardino
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina.,Laboratorio de Neuroepigenética
| | - Marcelo J Wolansky
- Laboratorio de Toxicología de Mezclas Químicas; .,Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina.,IQUIBICEN-Argentina National Research Council (CONICET)
| | - Mónica L Kotler
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina.,IQUIBICEN-Argentina National Research Council (CONICET).,Laboratorio de Disfunción Celular en Enfermedades Neurodegenerativas y Nanomedicina
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Abstract
Ion channels no longer belong to students of the neuron. The development of the patch- clamp technique has triggered an avalanche of ion channel studies extending far beyond the initial investigations that tended to focus on neuronal excitability. Studies of basic cell properties, even in cells other than neurons, now routinely include the evaluation of a cell's electrophysiological features and have yielded a large and growing database con cerning the electrophysiological properties of inexcitable cells. These include such cells as fibroblasts, macrophages, glial cells, bone cells, epithelial cells, and even plant cells, to name but a few, and the electrophysiological properties of these cells are as wide ranging as their cell functions and tissue origins. The Neuroscientist 1:64-67, 1995
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31
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Kimelberg HK. ■ Review : Cell Volume in the CNS: Regulation and Implications for Nervous System Function and Pathology. Neuroscientist 2016. [DOI: 10.1177/107385840000600110] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Swelling of cells in the nervous system is frequently associated with pathological states such as cerebral ischemia. The major cell type that swells in gray matter appears to be the astrocyte, although swelling of neuronal dendrites also occurs. Such swelling probably affects function by reducing the volume of the extracellular space. In addition the properties of the swollen cells themselves are altered, such as the swelling-induced release of excitatory amino acids, which are likely to be deleterious. Recent work has shown that these effects, linked to astrocytic swelling, may be involved in pathological states such as cerebral ischemia and trauma. Increased understanding of such swelling in the CNS will thus be of great importance in understanding mechanisms of brain damage and may provide specific sites for therapeutic intervention. NEUROSCIENTIST 6:14-25, 2000
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Abstract
Since their discovery in the late nineteenth century, glial cells have taken a backstage role to neurons in our investigations of the nervous system. Yet, in the mammalian brain, glial cells outnumber neurons and comprise 50% of the brain volume. A number of proteins, including important synthetic enzymes, are located almost exclusively in glia, suggesting that glial cells may serve functions beyond providing structural support. Speculations of more active roles for glial cells in brain function began at the turn of the century, at which time it had been suggested that they serve nutritive functions (Golgi, 1885), insulate nerve fibers (Ramon y Cajal, 1909), phagocytose dying neurons (Marinesco, 1896), secrete fac tors (Achucarro, 1915), and remove neurotransmitters (the substances by which one nerve cell excites another) from the synaptic cleft (Lugaro, 1907). Many of these early hypotheses have subsequently gained experimental support; however, our understanding of glial roles in brain function is still limited. The Neuroscientist 1:123-126, 1995
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Tao Y, Chen T, Liu B, Wang LQ, Peng GH, Qin LM, Yan ZJ, Huang YF. The transcorneal electrical stimulation as a novel therapeutic strategy against retinal and optic neuropathy: a review of experimental and clinical trials. Int J Ophthalmol 2016; 9:914-9. [PMID: 27366697 DOI: 10.18240/ijo.2016.06.21] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 02/25/2016] [Indexed: 01/29/2023] Open
Abstract
Transcorneal electrical stimulation (TES) is a novel therapeutic approach to activate the retina and related downstream structures. TES has multiple advantages over traditional treatments, such as being minimally invasive and readily applicable in a routine manner. Series of animal experiments have shown that TES protects the retinal neuron from traumatic or genetic induced degeneration. These laboratory evidences support its utilization in ophthalmological therapies against various retinal and optical diseases including retinitis pigmentosa (RP), traumatic optic neuropathy, anterior ischemic optic neuropathy (AION), and retinal artery occlusions (RAOs). Several pioneering explorations sought to clarify the functional mechanism underlying the neuroprotective effects of TES. It seems that the neuroprotective effects should not be attributed to a solitary pathway, on the contrary, multiple mechanisms might contribute collectively to maintain cellular homeostasis and promote cell survival in the retina. More precise evaluations via functional and morphological techniques would determine the exact mechanism underlying the remarkable neuroprotective effect of TES. Further studies to determine the optimal parameters and the long-term stability of TES are crucial to justify the clinical significance and to establish TES as a popularized therapeutic modality against retinal and optic neuropathy.
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Affiliation(s)
- Ye Tao
- Department of Ophthalmology, Ophthalmology & Visual Science Key Lab of PLA, General Hospital of Chinese PLA, Beijing 100853, China
| | - Tao Chen
- Department of Clinical Aerospace Medicine, the Fourth Military Medical University, Xi'an 710032, Shaanxi Province, China
| | - Bei Liu
- Department of Neurosurgery and Institute for Functional Brain Disorders, Tangdu Hospital, the Fourth Military Medical University, Xi'an 710038, Shaanxi Province, China
| | - Li-Qiang Wang
- Department of Ophthalmology, Ophthalmology & Visual Science Key Lab of PLA, General Hospital of Chinese PLA, Beijing 100853, China
| | - Guang-Hua Peng
- Department of Ophthalmology, Ophthalmology & Visual Science Key Lab of PLA, General Hospital of Chinese PLA, Beijing 100853, China
| | - Li-Min Qin
- Department of Ophthalmology, Ophthalmology & Visual Science Key Lab of PLA, General Hospital of Chinese PLA, Beijing 100853, China
| | - Zhong-Jun Yan
- Department of Neurosurgery and Institute for Functional Brain Disorders, Tangdu Hospital, the Fourth Military Medical University, Xi'an 710038, Shaanxi Province, China
| | - Yi-Fei Huang
- Department of Ophthalmology, Ophthalmology & Visual Science Key Lab of PLA, General Hospital of Chinese PLA, Beijing 100853, China
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Ding F, O'Donnell J, Xu Q, Kang N, Goldman N, Nedergaard M. Changes in the composition of brain interstitial ions control the sleep-wake cycle. Science 2016; 352:550-5. [PMID: 27126038 PMCID: PMC5441687 DOI: 10.1126/science.aad4821] [Citation(s) in RCA: 234] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 03/24/2016] [Indexed: 12/29/2022]
Abstract
Wakefulness is driven by the widespread release of neuromodulators by the ascending arousal system. Yet, it is unclear how these substances orchestrate state-dependent, global changes in neuronal activity. Here, we show that neuromodulators induce increases in the extracellular K(+) concentration ([K(+)]e) in cortical slices electrically silenced by tetrodotoxin. In vivo, arousal was linked to AMPA receptor-independent elevations of [K(+)]e concomitant with decreases in [Ca(2+)]e, [Mg(2+)]e, [H(+)]e, and the extracellular volume. Opposite, natural sleep and anesthesia reduced [K(+)]e while increasing [Ca(2+)]e, [Mg(2+)]e, and [H(+)]e as well as the extracellular volume. Local cortical activity of sleeping mice could be readily converted to the stereotypical electroencephalography pattern of wakefulness by simply imposing a change in the extracellular ion composition. Thus, extracellular ions control the state-dependent patterns of neural activity.
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Affiliation(s)
- Fengfei Ding
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA. Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - John O'Donnell
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Qiwu Xu
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Ning Kang
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Nanna Goldman
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA. Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2200, Denmark.
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A Novel Mechanism of pH Buffering in C. elegans Glia: Bicarbonate Transport via the Voltage-Gated ClC Cl- Channel CLH-1. J Neurosci 2016; 35:16377-97. [PMID: 26674864 DOI: 10.1523/jneurosci.3237-15.2015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED An important function of glia is the maintenance of the ionic composition and pH of the synaptic microenvironment. In terms of pH regulation, HCO3 (-) buffering has been shown to be important in both glia and neurons. Here, we used in vivo fluorescent pH imaging and RNA sequencing of the amphid sheath glia of Caenorhabditis elegans to reveal a novel mechanism of cellular HCO3 (-) uptake. While the classical mechanism of HCO3 (-) uptake involves Na(+)/HCO3 (-) cotransporters, here we demonstrate that the C. elegans ClC Cl(-) channel CLH-1 is highly permeable to HCO3 (-) and mediates HCO3 (-) uptake into amphid sheath glia. CLH-1 has homology and electrophysiological properties similar to the mammalian ClC-2 Cl(-) channel. Our data suggest that, in addition to maintaining synaptic Cl(-) concentration, these channels may also be involved in maintenance of synaptic pH via HCO3 (-) flux. These findings provide an exciting new facet of study regarding how pH is regulated in the brain. SIGNIFICANCE STATEMENT Maintenance of pH is essential for the physiological function of the nervous system. HCO3 (-) is crucial for pH regulation and is transported into the cell via ion transporters, including ion channels, the molecular identity of which remains unclear. In this manuscript, we describe our discovery that the C. elegans amphid sheath glia regulate intracellular pH via HCO3 (-) flux through the voltage-gated ClC channel CLH-1. This represents a novel function for ClC channels, which has implications for their possible role in mammalian glial pH regulation. This discovery may also provide a novel therapeutic target for pathologic conditions, such as ischemic stroke where acidosis leads to widespread death of glia and subsequently neurons.
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36
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Larsen BR, MacAulay N. Kir4.1-mediated spatial buffering of K(+): experimental challenges in determination of its temporal and quantitative contribution to K(+) clearance in the brain. Channels (Austin) 2015; 8:544-50. [PMID: 25483287 DOI: 10.4161/19336950.2014.970448] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Neuronal activity results in release of K(+) into the extracellular space of the central nervous system. If the excess K(+) is allowed to accumulate, neuronal firing will be compromised by the ensuing neuronal membrane depolarization. The surrounding glial cells are involved in clearing K(+) from the extracellular space by molecular mechanism(s), the identity of which have been a matter of controversy for over half a century. Kir4.1-mediated spatial buffering of K(+) has been promoted as a major contributor to K(+) removal although its quantitative and temporal contribution has remained undefined. We discuss the biophysical and experimental challenges regarding determination of the contribution of Kir4.1 to extracellular K(+) management during neuronal activity. It is concluded that 1) the geometry of the experimental preparation is crucial for detection of Kir4.1-mediated spatial buffering and 2) Kir4.1 enacts spatial buffering of K(+) during but not after neuronal activity.
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Affiliation(s)
- Brian Roland Larsen
- a Department of Cellular and Molecular Medicine; Faculty of Health and Medical Sciences ; University of Copenhagen ; Copenhagen , Denmark
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37
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Lee DY. Roles of mTOR Signaling in Brain Development. Exp Neurobiol 2015; 24:177-85. [PMID: 26412966 PMCID: PMC4580744 DOI: 10.5607/en.2015.24.3.177] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 09/02/2015] [Accepted: 09/02/2015] [Indexed: 12/18/2022] Open
Abstract
mTOR is a serine/threonine kinase composed of multiple protein components. Intracellular signaling of mTOR complexes is involved in many of physiological functions including cell survival, proliferation and differentiation through the regulation of protein synthesis in multiple cell types. During brain development, mTOR-mediated signaling pathway plays a crucial role in the process of neuronal and glial differentiation and the maintenance of the stemness of neural stem cells. The abnormalities in the activity of mTOR and its downstream signaling molecules in neural stem cells result in severe defects of brain developmental processes causing a significant number of brain disorders, such as pediatric brain tumors, autism, seizure, learning disability and mental retardation. Understanding the implication of mTOR activity in neural stem cells would be able to provide an important clue in the development of future brain developmental disorder therapies.
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Affiliation(s)
- Da Yong Lee
- Stem Cell Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
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38
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Kadala A, Verdier D, Morquette P, Kolta A. Ion Homeostasis in Rhythmogenesis: The Interplay Between Neurons and Astroglia. Physiology (Bethesda) 2015; 30:371-88. [DOI: 10.1152/physiol.00023.2014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Proper function of all excitable cells depends on ion homeostasis. Nowhere is this more critical than in the brain where the extracellular concentration of some ions determines neurons' firing pattern and ability to encode information. Several neuronal functions depend on the ability of neurons to change their firing pattern to a rhythmic bursting pattern, whereas, in some circuits, rhythmic firing is, on the contrary, associated to pathologies like epilepsy or Parkinson's disease. In this review, we focus on the four main ions known to fluctuate during rhythmic firing: calcium, potassium, sodium, and chloride. We discuss the synergistic interactions between these elements to promote an oscillatory activity. We also review evidence supporting an important role for astrocytes in the homeostasis of each of these ions and describe mechanisms by which astrocytes may regulate neuronal firing by altering their extracellular concentrations. A particular emphasis is put on the mechanisms underlying rhythmogenesis in the circuit forming the central pattern generator (CPG) for mastication and other CPG systems. Finally, we discuss how an impairment in the ability of glial cells to maintain such homeostasis may result in pathologies like epilepsy and Parkinson's disease.
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Affiliation(s)
- Aklesso Kadala
- Département de Neurosciences and Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, Québec, Canada; and
| | - Dorly Verdier
- Département de Neurosciences and Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, Québec, Canada; and
| | - Philippe Morquette
- Département de Neurosciences and Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, Québec, Canada; and
| | - Arlette Kolta
- Département de Neurosciences and Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, Québec, Canada; and
- Faculté de Médecine Dentaire and Réseau de Recherche en Santé Bucco-dentaire et Osseuse du Fonds de Recherche Québec-Santé, Université de Montréal, Montréal, Québec, Canada
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Activity-Dependent Plasticity of Astroglial Potassium and Glutamate Clearance. Neural Plast 2015; 2015:109106. [PMID: 26346563 PMCID: PMC4539499 DOI: 10.1155/2015/109106] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 04/17/2015] [Indexed: 12/21/2022] Open
Abstract
Recent evidence has shown that astrocytes play essential roles in synaptic transmission and plasticity. Nevertheless, how neuronal activity alters astroglial functional properties and whether such properties also display specific forms of plasticity still remain elusive. Here, we review research findings supporting this aspect of astrocytes, focusing on their roles in the clearance of extracellular potassium and glutamate, two neuroactive substances promptly released during excitatory synaptic transmission. Their subsequent removal, which is primarily carried out by glial potassium channels and glutamate transporters, is essential for proper functioning of the brain. Similar to neurons, different forms of short- and long-term plasticity in astroglial uptake have been reported. In addition, we also present novel findings showing robust potentiation of astrocytic inward currents in response to repetitive stimulations at mild frequencies, as low as 0.75 Hz, in acute hippocampal slices. Interestingly, neurotransmission was hardly affected at this frequency range, suggesting that astrocytes may be more sensitive to low frequency stimulation and may exhibit stronger plasticity than neurons to prevent hyperexcitability. Taken together, these important findings strongly indicate that astrocytes display both short- and long-term plasticity in their clearance of excess neuroactive substances from the extracellular space, thereby regulating neuronal activity and brain homeostasis.
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Rocha PRF, Schlett P, Schneider L, Dröge M, Mailänder V, Gomes HL, Blom PWM, de Leeuw DM. Low frequency electric current noise in glioma cell populations. J Mater Chem B 2015; 3:5035-5039. [PMID: 32262456 DOI: 10.1039/c5tb00144g] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Measuring the electrical activity of large and defined populations of cells is currently a major technical challenge to electrophysiology, especially in the picoampere-range. For this purpose, we developed and applied a bidirectional transducer based on a chip with interdigitated gold electrodes to record the electrical response of cultured glioma cells. Recent research determined that also non-neural brain glia cells are electrically active and excitable. Their transformed counterparts, e.g. glioma cells, were suggested to partially retain these electric features. Such electrophysiological studies however are usually performed on individual cells and are limited in their predictive power for the overall electrical activity of the multicellular tumour bulk. Our extremely low-noise measuring system allowed us to detect not only prominent electrical bursts of neuronal cells but also minute, yet constantly occurring and functional, membrane capacitive current oscillations across large populations of C6 glioma cells, which we termed electric current noise. At the same time, tumour cells of non-brain origin (HeLa) proved to be electrically quiescent in comparison. Finally, we determined that the glioma cell activity is primarily caused by the opening of voltage-gated Na+ and K+ ion channels and can be efficiently abolished using specific pharmacological inhibitors. Thus, we offer here a unique approach for studying electrophysiological properties of large cancer cell populations as an in vitro reference for tumour bulks in vivo.
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Affiliation(s)
- P R F Rocha
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany.
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Sepúlveda FV, Pablo Cid L, Teulon J, Niemeyer MI. Molecular aspects of structure, gating, and physiology of pH-sensitive background K2P and Kir K+-transport channels. Physiol Rev 2015; 95:179-217. [PMID: 25540142 DOI: 10.1152/physrev.00016.2014] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
K(+) channels fulfill roles spanning from the control of excitability to the regulation of transepithelial transport. Here we review two groups of K(+) channels, pH-regulated K2P channels and the transport group of Kir channels. After considering advances in the molecular aspects of their gating based on structural and functional studies, we examine their participation in certain chosen physiological and pathophysiological scenarios. Crystal structures of K2P and Kir channels reveal rather unique features with important consequences for the gating mechanisms. Important tasks of these channels are discussed in kidney physiology and disease, K(+) homeostasis in the brain by Kir channel-equipped glia, and central functions in the hearing mechanism in the inner ear and in acid secretion by parietal cells in the stomach. K2P channels fulfill a crucial part in central chemoreception probably by virtue of their pH sensitivity and are central to adrenal secretion of aldosterone. Finally, some unorthodox behaviors of the selectivity filters of K2P channels might explain their normal and pathological functions. Although a great deal has been learned about structure, molecular details of gating, and physiological functions of K2P and Kir K(+)-transport channels, this has been only scratching at the surface. More molecular and animal studies are clearly needed to deepen our knowledge.
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Affiliation(s)
- Francisco V Sepúlveda
- Centro de Estudios Científicos, Valdivia, Chile; UPMC Université Paris 06, Team 3, Paris, France; and Institut National de la Santé et de la Recherche Médicale, UMR_S 1138, Paris, France
| | - L Pablo Cid
- Centro de Estudios Científicos, Valdivia, Chile; UPMC Université Paris 06, Team 3, Paris, France; and Institut National de la Santé et de la Recherche Médicale, UMR_S 1138, Paris, France
| | - Jacques Teulon
- Centro de Estudios Científicos, Valdivia, Chile; UPMC Université Paris 06, Team 3, Paris, France; and Institut National de la Santé et de la Recherche Médicale, UMR_S 1138, Paris, France
| | - María Isabel Niemeyer
- Centro de Estudios Científicos, Valdivia, Chile; UPMC Université Paris 06, Team 3, Paris, France; and Institut National de la Santé et de la Recherche Médicale, UMR_S 1138, Paris, France
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42
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Perea G, Sur M, Araque A. Neuron-glia networks: integral gear of brain function. Front Cell Neurosci 2014; 8:378. [PMID: 25414643 PMCID: PMC4222327 DOI: 10.3389/fncel.2014.00378] [Citation(s) in RCA: 143] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 10/22/2014] [Indexed: 12/21/2022] Open
Abstract
Astrocytes, the most abundant glial cell in the brain, play critical roles in metabolic and homeostatic functions of the Nervous System; however, their participation in coding information and cognitive processes has been largely ignored. The strategic position of astrocyte processes facing synapses and the astrocyte ability to uptake neurotransmitters and release neuroactive substances, so-called “gliotransmitters”, provide the scenario for prolific neuron-astrocyte signaling. From studies at single-cell level to animal behavior, recent advances in technology and genetics have revealed the impact of astrocyte activity in brain function from cellular and synaptic physiology, neuronal circuits to behavior. The present review critically discusses the consequences of astrocyte signaling on synapses and networks, as well as its impact on neuronal information processing, showing that some crucial brain functions arise from the coordinated activity of neuron-glia networks.
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Affiliation(s)
- Gertrudis Perea
- Functional and System Neurobiology, Instituto Cajal, Consejo Superior de Investigaciones Científicas Madrid, Spain
| | - Mriganka Sur
- Department of Brain and Cognitive Sciences, Picower Institute for Learning and Memory, Massachusetts Institute of Technology Cambridge, MA, USA
| | - Alfonso Araque
- Department of Neuroscience, University of Minnesota, Minneapolis MN, USA
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Flores-Méndez M, Ramírez D, Alamillo N, Hernández-Kelly LC, Del Razo LM, Ortega A. Fluoride exposure regulates the elongation phase of protein synthesis in cultured Bergmann glia cells. Toxicol Lett 2014; 229:126-33. [PMID: 24954634 DOI: 10.1016/j.toxlet.2014.06.022] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 06/12/2014] [Accepted: 06/13/2014] [Indexed: 01/07/2023]
Abstract
Fluoride is an environmental pollutant present in dental products, food, pesticides and water. The latter, is the greatest source of exposure to this contaminant. Structural and functional damages to the central nervous system are present in exposed population. An established consequence of the neuronal is the release of a substantial amount of glutamate to the extracellular space, leading to an excitotoxic insult. Glutamate exerts its actions through the activation of specific plasma membrane receptors and transporters present in neurons and in glia cells and it is the over-activation of glutamate receptors and transporters, the biochemical hallmark of neuronal and oligodendrocyte cell death. In this context, taking into consideration that fluoride leads to degeneration of cerebellar cells, we took the advantage of the well-established model of cerebellar Bergmann glia cultures to gain insight into the molecular mechanisms inherent to fluoride neurotoxicity that might be triggered in glia cells. We could establish that fluoride decreases [(35)S]-methionine incorporation into newly synthesized polypeptides, in a time-dependent manner, and that this halt in protein synthesis is the result of a decrease in the elongation phase of translation, mediated by an augmentation of eukaryotic elongation factor 2 phosphorylation. These results favor the notion of glial cells as targets of fluoride toxicity and strengthen the idea of a critical involvement of glia cells in the function and dysfunction of the brain.
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Affiliation(s)
- Marco Flores-Méndez
- Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Apartado Postal 14-740, México D.F. 07300, Mexico.
| | - Diana Ramírez
- Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Apartado Postal 14-740, México D.F. 07300, Mexico
| | - Nely Alamillo
- Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Apartado Postal 14-740, México D.F. 07300, Mexico.
| | - Luisa C Hernández-Kelly
- Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Apartado Postal 14-740, México D.F. 07300, Mexico.
| | - Luz María Del Razo
- Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Apartado Postal 14-740, México D.F. 07300, Mexico.
| | - Arturo Ortega
- Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Apartado Postal 14-740, México D.F. 07300, Mexico.
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Gu XQ, Pamenter ME, Siemen D, Sun X, Haddad GG. Mitochondrial but not plasmalemmal BK channels are hypoxia-sensitive in human glioma. Glia 2014; 62:504-13. [PMID: 24446243 DOI: 10.1002/glia.22620] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 12/09/2013] [Accepted: 12/10/2013] [Indexed: 11/05/2022]
Abstract
Tumor cells are resistant to hypoxia but the underlying mechanism(s) of this tolerance remain poorly understood. In healthy brain cells, plasmalemmal Ca(2+)-activated K(+) channels ((plasma)BK) function as oxygen sensors and close under hypoxic conditions. Similarly, BK channels in the mitochondrial inner membrane ((mito)BK) are also hypoxia sensitive and regulate reactive oxygen species production and also permeability transition pore formation. Both channel populations are therefore well situated to mediate cellular responses to hypoxia. In tumors, BK channel expression increases with malignancy, suggesting these channels contribute to tumor growth; therefore, we hypothesized that the sensitivity of (plasma)BK and/or (mito)BK to hypoxia differs between glioma and healthy brain cells. To test this, we examined the electrophysiological properties of (plasma)BK and (mito)BK from a human glioma cell line during normoxia and hypoxia. We observed single channel activities in whole cells and isolated mitoplasts with slope conductance of 199 ± 8 and 278 ± 10 pA, respectively. These currents were Ca(2+)- and voltage-dependent, and were inhibited by the BK channel antagonist charybdotoxin (0.1 μM). (plasma)BK could only be activated at membrane potentials >+40 mV and had a low open probability (NPo) that was unchanged by hypoxia. Conversely, (mito)BK were active across a range of membrane potentials (-40 to +40 mV) and their NPo increased during hypoxia. Activating (plasma)BK, but not (mito)BK induced cell death and this effect was enhanced during hypoxia. We conclude that unlike in healthy brain cells, glioma (mito)BK channels, but not (plasma)BK channels are oxygen sensitive.
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Affiliation(s)
- Xiang Q Gu
- Section of Respiratory Medicine, Department of Pediatrics, University of California San Diego, La Jolla, California
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45
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Cataldi M. The changing landscape of voltage-gated calcium channels in neurovascular disorders and in neurodegenerative diseases. Curr Neuropharmacol 2013; 11:276-97. [PMID: 24179464 PMCID: PMC3648780 DOI: 10.2174/1570159x11311030004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 02/02/2013] [Accepted: 02/14/2013] [Indexed: 12/12/2022] Open
Abstract
It is a common belief that voltage-gated calcium channels (VGCC) cannot carry toxic amounts of Ca2+ in neurons. Also, some of them as L-type channels are essential for Ca2+-dependent regulation of prosurvival gene-programs. However, a wealth of data show a beneficial effect of drugs acting on VGCCs in several neurodegenerative and neurovascular diseases. In the present review, we explore several mechanisms by which the “harmless” VGCCs may become “toxic” for neurons. These mechanisms could explain how, though usually required for neuronal survival, VGCCs may take part in neurodegeneration. We will present evidence showing that VGCCs can carry toxic Ca2+ when: a) their density or activity increases because of aging, chronic hypoxia or exposure to β-amyloid peptides or b) Ca2+-dependent action potentials carry high Ca2+ loads in pacemaker neurons. Besides, we will examine conditions in which VGCCs promote neuronal cell death without carrying excess Ca2+. This can happen, for instance, when they carry metal ions into the neuronal cytoplasm or when a pathological decrease in their activity weakens Ca2+-dependent prosurvival gene programs. Finally, we will explore the role of VGCCs in the control of nonneuronal cells that take part to neurodegeneration like those of the neurovascular unit or of microglia.
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Affiliation(s)
- Mauro Cataldi
- Division of Pharmacology, Department of Neuroscience, Reproductive and Odontostomatological Sciences, Federico II University of Naples, Italy
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46
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Comes N, Bielanska J, Vallejo-Gracia A, Serrano-Albarrás A, Marruecos L, Gómez D, Soler C, Condom E, Ramón Y Cajal S, Hernández-Losa J, Ferreres JC, Felipe A. The voltage-dependent K(+) channels Kv1.3 and Kv1.5 in human cancer. Front Physiol 2013; 4:283. [PMID: 24133455 PMCID: PMC3794381 DOI: 10.3389/fphys.2013.00283] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 09/18/2013] [Indexed: 11/20/2022] Open
Abstract
Voltage-dependent K+ channels (Kv) are involved in a number of physiological processes, including immunomodulation, cell volume regulation, apoptosis as well as differentiation. Some Kv channels participate in the proliferation and migration of normal and tumor cells, contributing to metastasis. Altered expression of Kv1.3 and Kv1.5 channels has been found in several types of tumors and cancer cells. In general, while the expression of Kv1.3 apparently exhibits no clear pattern, Kv1.5 is induced in many of the analyzed metastatic tissues. Interestingly, evidence indicates that Kv1.5 channel shows inversed correlation with malignancy in some gliomas and non-Hodgkin's lymphomas. However, Kv1.3 and Kv1.5 are similarly remodeled in some cancers. For instance, expression of Kv1.3 and Kv1.5 correlates with a certain grade of tumorigenicity in muscle sarcomas. Differential remodeling of Kv1.3 and Kv1.5 expression in human cancers may indicate their role in tumor growth and their importance as potential tumor markers. However, despite of this increasing body of information, which considers Kv1.3 and Kv1.5 as emerging tumoral markers, further research must be performed to reach any conclusion. In this review, we summarize what it has been lately documented about Kv1.3 and Kv1.5 channels in human cancer.
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Affiliation(s)
- Núria Comes
- Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina, Universitat de Barcelona Barcelona, Spain
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Dallérac G, Chever O, Rouach N. How do astrocytes shape synaptic transmission? Insights from electrophysiology. Front Cell Neurosci 2013; 7:159. [PMID: 24101894 PMCID: PMC3787198 DOI: 10.3389/fncel.2013.00159] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 09/02/2013] [Indexed: 02/01/2023] Open
Abstract
A major breakthrough in neuroscience has been the realization in the last decades that the dogmatic view of astroglial cells as being merely fostering and buffering elements of the nervous system is simplistic. A wealth of investigations now shows that astrocytes actually participate in the control of synaptic transmission in an active manner. This was first hinted by the intimate contacts glial processes make with neurons, particularly at the synaptic level, and evidenced using electrophysiological and calcium imaging techniques. Calcium imaging has provided critical evidence demonstrating that astrocytic regulation of synaptic efficacy is not a passive phenomenon. However, given that cellular activation is not only represented by calcium signaling, it is also crucial to assess concomitant mechanisms. We and others have used electrophysiological techniques to simultaneously record neuronal and astrocytic activity, thus enabling the study of multiple ionic currents and in depth investigation of neuro-glial dialogues. In the current review, we focus on the input such approach has provided in the understanding of astrocyte-neuron interactions underlying control of synaptic efficacy.
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Affiliation(s)
- Glenn Dallérac
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, CNRS UMR 7241, INSERM U1050, Collège de France Paris, France
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Stobart JL, Anderson CM. Multifunctional role of astrocytes as gatekeepers of neuronal energy supply. Front Cell Neurosci 2013; 7:38. [PMID: 23596393 PMCID: PMC3622037 DOI: 10.3389/fncel.2013.00038] [Citation(s) in RCA: 171] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 03/26/2013] [Indexed: 01/01/2023] Open
Abstract
Dynamic adjustments to neuronal energy supply in response to synaptic activity are critical for neuronal function. Glial cells known as astrocytes have processes that ensheath most central synapses and express G-protein-coupled neurotransmitter receptors and transporters that respond to neuronal activity. Astrocytes also release substrates for neuronal oxidative phosphorylation and have processes that terminate on the surface of brain arterioles and can influence vascular smooth muscle tone and local blood flow. Membrane receptor or transporter-mediated effects of glutamate represent a convergence point of astrocyte influence on neuronal bioenergetics. Astrocytic glutamate uptake drives glycolysis and subsequent shuttling of lactate from astrocytes to neurons for oxidative metabolism. Astrocytes also convert synaptically reclaimed glutamate to glutamine, which is returned to neurons for glutamate salvage or oxidation. Finally, astrocytes store brain energy currency in the form of glycogen, which can be mobilized to produce lactate for neuronal oxidative phosphorylation in response to glutamatergic neurotransmission. These mechanisms couple synaptically driven astrocytic responses to glutamate with release of energy substrates back to neurons to match demand with supply. In addition, astrocytes directly influence the tone of penetrating brain arterioles in response to glutamatergic neurotransmission, coordinating dynamic regulation of local blood flow. We will describe the role of astrocytes in neurometabolic and neurovascular coupling in detail and discuss, in turn, how astrocyte dysfunction may contribute to neuronal bioenergetic deficit and neurodegeneration. Understanding the role of astrocytes as a hub for neurometabolic and neurovascular coupling mechanisms is a critical underpinning for therapeutic development in a broad range of neurodegenerative disorders characterized by chronic generalized brain ischemia and brain microvascular dysfunction.
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Affiliation(s)
- Jillian L Stobart
- Division of Neurodegenerative Disorders, Department of Pharmacology and Therapeutics, St. Boniface Hospital Research, University of Manitoba Winnipeg, MB, Canada ; Department of Nuclear Medicine, Institute of Pharmacology and Toxicology, University of Zürich Zürich, Switzerland
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Abstract
Astrocytes play an important role in maintaining an optically suited milieu for neuronal functionality, and are involved in the progression and outcome of many neuropathological conditions. It becomes increasingly evident that astrocytes are significant contributors to HIV-1 associated neurological disorders by modulating the microenvironment in the central nervous system and releasing proinflammatory cytokines. Recent studies have revealed direct metabolic interactions between neurons and astrocytes observed particularly in HIV-1-associated neurological disorders by which astrocytic dysfunctions disregulate extracellular K+ homeostasis, intracellular calcium concentration, glutamate clearance, and blood brain barrier integrity and permeability. Such dysfunctions are amplified via gap junctions, directly or indirectly impacting surrounding neurons and significantly contributing to the pathogenesis of HIV-1-associated neuropathology. In this review, we tentatively address recent progresses on the roles astrocytes may play in HIV-1-associated neurotoxicity.
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Affiliation(s)
- Hoai Ton
- Neurophysiology Laboratory, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198-5880, USA
| | - Huangui Xiong
- Neurophysiology Laboratory, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198-5880, USA
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50
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Calcium signaling in glioma cells--the role of nucleotide receptors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 986:61-79. [PMID: 22879064 DOI: 10.1007/978-94-007-4719-7_4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Calcium signaling is probably one of the evolutionary oldest and the most common way by which the signal can be transmitted from the cell environment to the cytoplasmic calcium binding effectors. Calcium signal is fast and due to diversity of calcium binding proteins it may have a very broad effect on cell behavior. Being a crucial player in neuronal transmission it is also very important for glia physiology. It is responsible for the cross-talk between neurons and astrocytes, for microglia activation and motility. Changes in calcium signaling are also crucial for the behavior of transformed glioma cells. The present Chapter summarizes molecular mechanisms of calcium signal formation present in glial cells with a strong emphasis on extracellular nucleotide-evoked signaling pathways. Some aspects of glioma C6 signaling such as the cross-talk between P2Y(1) and P2Y(12) nucleotide receptors in calcium signal generation will be discussed in-depth, to show complexity of machinery engaged in formation of this signal. Moreover, possible mechanisms of modulation of the calcium signal in diverse environments there will be presented herein. Finally, the possible role of calcium signal in glioma motility is also discussed. This is a very important issue, since glioma cells, contrary to the vast majority of neoplastic cells, cannot spread in the body with the bloodstream and, at least in early stages of tumor development, may expand only by means of sheer motility.
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