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Puebla M, Muñoz MF, Lillo MA, Contreras JE, Figueroa XF. Control of astrocytic Ca 2+ signaling by nitric oxide-dependent S-nitrosylation of Ca 2+ homeostasis modulator 1 channels. Biol Res 2024; 57:19. [PMID: 38689353 PMCID: PMC11059852 DOI: 10.1186/s40659-024-00503-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 04/18/2024] [Indexed: 05/02/2024] Open
Abstract
BACKGROUND Astrocytes Ca2+ signaling play a central role in the modulation of neuronal function. Activation of metabotropic glutamate receptors (mGluR) by glutamate released during an increase in synaptic activity triggers coordinated Ca2+ signals in astrocytes. Importantly, astrocytes express the Ca2+-dependent nitric oxide (NO)-synthetizing enzymes eNOS and nNOS, which might contribute to the Ca2+ signals by triggering Ca2+ influx or ATP release through the activation of connexin 43 (Cx43) hemichannels, pannexin-1 (Panx-1) channels or Ca2+ homeostasis modulator 1 (CALHM1) channels. Hence, we aim to evaluate the participation of NO in the astrocytic Ca2+ signaling initiated by stimulation of mGluR in primary cultures of astrocytes from rat brain cortex. RESULTS Astrocytes were stimulated with glutamate or t-ACPD and NO-dependent changes in [Ca2+]i and ATP release were evaluated. In addition, the activity of Cx43 hemichannels, Panx-1 channels and CALHM1 channels was also analyzed. The expression of Cx43, Panx-1 and CALHM1 in astrocytes was confirmed by immunofluorescence analysis and both glutamate and t-ACPD induced NO-mediated activation of CALHM1 channels via direct S-nitrosylation, which was further confirmed by assessing CALHM1-mediated current using the two-electrode voltage clamp technique in Xenopus oocytes. Pharmacological blockade or siRNA-mediated inhibition of CALHM1 expression revealed that the opening of these channels provides a pathway for ATP release and the subsequent purinergic receptor-dependent activation of Cx43 hemichannels and Panx-1 channels, which further contributes to the astrocytic Ca2+ signaling. CONCLUSIONS Our findings demonstrate that activation of CALHM1 channels through NO-mediated S-nitrosylation in astrocytes in vitro is critical for the generation of glutamate-initiated astrocytic Ca2+ signaling.
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Affiliation(s)
- Mariela Puebla
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, 8330025, Santiago, Chile
| | - Manuel F Muñoz
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, 8330025, Santiago, Chile
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA, USA
| | - Mauricio A Lillo
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ, USA
| | - Jorge E Contreras
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA, USA
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ, USA
| | - Xavier F Figueroa
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, 8330025, Santiago, Chile.
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2
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Zapata-Acevedo JF, Mantilla-Galindo A, Vargas-Sánchez K, González-Reyes RE. Blood-brain barrier biomarkers. Adv Clin Chem 2024; 121:1-88. [PMID: 38797540 DOI: 10.1016/bs.acc.2024.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
The blood-brain barrier (BBB) is a dynamic interface that regulates the exchange of molecules and cells between the brain parenchyma and the peripheral blood. The BBB is mainly composed of endothelial cells, astrocytes and pericytes. The integrity of this structure is essential for maintaining brain and spinal cord homeostasis and protection from injury or disease. However, in various neurological disorders, such as traumatic brain injury, Alzheimer's disease, and multiple sclerosis, the BBB can become compromised thus allowing passage of molecules and cells in and out of the central nervous system parenchyma. These agents, however, can serve as biomarkers of BBB permeability and neuronal damage, and provide valuable information for diagnosis, prognosis and treatment. Herein, we provide an overview of the BBB and changes due to aging, and summarize current knowledge on biomarkers of BBB disruption and neurodegeneration, including permeability, cellular, molecular and imaging biomarkers. We also discuss the challenges and opportunities for developing a biomarker toolkit that can reliably assess the BBB in physiologic and pathophysiologic states.
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Affiliation(s)
- Juan F Zapata-Acevedo
- Grupo de Investigación en Neurociencias, Centro de Neurociencia Neurovitae-UR, Instituto de Medicina Traslacional, Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá, Colombia
| | - Alejandra Mantilla-Galindo
- Grupo de Investigación en Neurociencias, Centro de Neurociencia Neurovitae-UR, Instituto de Medicina Traslacional, Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá, Colombia
| | - Karina Vargas-Sánchez
- Laboratorio de Neurofisiología Celular, Grupo de Neurociencia Traslacional, Facultad de Medicina, Universidad de los Andes, Bogotá, Colombia
| | - Rodrigo E González-Reyes
- Grupo de Investigación en Neurociencias, Centro de Neurociencia Neurovitae-UR, Instituto de Medicina Traslacional, Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá, Colombia.
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3
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Lalo U, Pankratov Y. ATP-mediated signalling in the central synapses. Neuropharmacology 2023; 229:109477. [PMID: 36841527 DOI: 10.1016/j.neuropharm.2023.109477] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 02/13/2023] [Accepted: 02/23/2023] [Indexed: 02/27/2023]
Abstract
ATP released from the synaptic terminals and astrocytes can activate neuronal P2 receptors at a variety of locations across the CNS. Although the postsynaptic ATP-mediated signalling does not bring a major contribution into the excitatory transmission, it is instrumental for slow and diffuse modulation of synaptic dynamics and neuronal firing in many CNS areas. Neuronal P2X and P2Y receptors can be activated by ATP released from the synaptic terminals, astrocytes and microglia and thereby can participate in the regulation of synaptic homeostasis and plasticity. There is growing evidence of importance of purinergic regulation of synaptic transmission in different physiological and pathological contexts. Here, we review the main mechanisms underlying the complexity and diversity of purinergic signalling and purinergic modulation in central neurons.
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Affiliation(s)
- Ulyana Lalo
- School of Life Sciences, University of Warwick, United Kingdom
| | - Yuriy Pankratov
- School of Life Sciences, University of Warwick, United Kingdom.
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4
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Steinruecke M, Lonergan RM, Selvaraj BT, Chandran S, Diaz-Castro B, Stavrou M. Blood-CNS barrier dysfunction in amyotrophic lateral sclerosis: Proposed mechanisms and clinical implications. J Cereb Blood Flow Metab 2023; 43:642-654. [PMID: 36704819 PMCID: PMC10108188 DOI: 10.1177/0271678x231153281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
There is strong evidence for blood-brain and blood-spinal cord barrier dysfunction at the early stages of many neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). Since impairment of the blood-central nervous system barrier (BCNSB) occurs during the pre-symptomatic stages of ALS, the mechanisms underlying this pathology are likely also involved in the ALS disease process. In this review, we explore how drivers of ALS disease, particularly mitochondrial dysfunction, astrocyte pathology and neuroinflammation, may contribute to BCNSB impairment. Mitochondria are highly abundant in BCNSB tissue and mitochondrial dysfunction in ALS contributes to motor neuron death. Likewise, astrocytes adopt key physical, transport and metabolic functions at the barrier, many of which are impaired in ALS. Astrocytes also show raised expression of inflammatory markers in ALS and ablating ALS-causing transgenes in astrocytes slows disease progression. In addition, key drivers of neuroinflammation, including TAR DNA-binding protein 43 (TDP-43) pathology, matrix metalloproteinase activation and systemic inflammation, affect BCNSB integrity in ALS. Finally, we discuss the translational implications of BCNSB dysfunction in ALS, including the development of biomarkers for disease onset and progression, approaches aimed at restoring BCNSB integrity and in vitro modelling of the neurogliovascular system.
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Affiliation(s)
- Moritz Steinruecke
- Edinburgh Medical School, The University of Edinburgh, Edinburgh, UK.,University of Cambridge School of Clinical Medicine, Cambridge, UK
| | | | - Bhuvaneish T Selvaraj
- Euan MacDonald Centre for MND Research, The University of Edinburgh, Edinburgh, UK.,Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK.,Dementia Research Institute at The University of Edinburgh, Edinburgh, UK
| | - Siddharthan Chandran
- Euan MacDonald Centre for MND Research, The University of Edinburgh, Edinburgh, UK.,Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK.,Dementia Research Institute at The University of Edinburgh, Edinburgh, UK
| | - Blanca Diaz-Castro
- Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK.,Dementia Research Institute at The University of Edinburgh, Edinburgh, UK
| | - Maria Stavrou
- Euan MacDonald Centre for MND Research, The University of Edinburgh, Edinburgh, UK.,Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK.,Dementia Research Institute at The University of Edinburgh, Edinburgh, UK
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5
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Behl T, Rana T, Sehgal A, Makeen HA, Albratty M, Alhazmi HA, Meraya AM, Bhatia S, Sachdeva M. Phytochemicals targeting nitric oxide signaling in neurodegenerative diseases. Nitric Oxide 2023; 130:1-11. [PMID: 36375788 DOI: 10.1016/j.niox.2022.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 10/25/2022] [Accepted: 11/07/2022] [Indexed: 11/13/2022]
Abstract
Neurodegenerative diseases are a set of diseases in which slow and progressive neuronal loss occurs. Nitric oxide (NO) as a neurotransmitter performs key roles in the stimulation and blockade of various inflammatory processes. Although physiological NO is necessary for protection against a variety of pathogens, reactive oxygen species-mediated oxidative stress induces inflammatory cascades and apoptosis. Activation of glial cells particularly astrocytes and microglia induce overproduction of NO, resulting in neuroinflammation and neurodegenerative disorders. Hence, inhibiting the overproduction of NO is a beneficial therapeutic approach for numerous neuroinflammatory conditions. Several compounds have been explored for the management of neurodegenerative disorders, but they have minor symptomatic benefits and several adverse effects. Phytochemicals have currently gained more consideration owing to their ability to reduce the overproduction of NO in neurodegenerative disorders. Furthermore, phytochemicals are generally considered to be safe and beneficial. The mechanisms of NO generation and their implications in neurodegenerative disorders are explored in this review article, as well as several newly discovered phytochemicals that might have NO inhibitory activity. The current review could aid in the discovery of new anti-neuroinflammatory drugs that can suppress NO generation, particularly during neuroinflammatory and neurodegenerative conditions.
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Affiliation(s)
- Tapan Behl
- School of Health Sciences and Technology, University of Petroleum and Energy Studies, Bidholi, Dehradun, India.
| | - Tarapati Rana
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
| | - Aayush Sehgal
- GHG Khalsa College of Pharmacy, Gurusar Sadhar, Punjab, India
| | - Hafiz A Makeen
- Pharmacy Practice Research Unit, Clinical Pharmacy Department, College of Pharmacy, Jazan University, Saudi Arabia
| | - Mohammed Albratty
- Department of Pharmaceutical Chemistry, College of Pharmacy, Jazan University, Jazan, Saudi Arabia
| | - Hassan A Alhazmi
- Department of Pharmaceutical Chemistry, College of Pharmacy, Jazan University, Jazan, Saudi Arabia; Substance Abuse and Toxicology Research Center, Jazan University, Jazan, Saudi Arabia
| | - Abdulkarim M Meraya
- Pharmacy Practice Research Unit, Department of Clinical Pharmacy, College of Pharmacy, Jazan University, Saudi Arabia
| | - Saurabh Bhatia
- Natural & Medical Sciences Research Centre, University of Nizwa, Birkat Al Mauz, Nizwa, Oman
| | - Monika Sachdeva
- Fatima College of Health Science, Al Ain, United Arab Emirates
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6
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Kim J, Thomas SN. Opportunities for Nitric Oxide in Potentiating Cancer Immunotherapy. Pharmacol Rev 2022; 74:1146-1175. [PMID: 36180108 PMCID: PMC9553106 DOI: 10.1124/pharmrev.121.000500] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 05/15/2022] [Accepted: 07/05/2022] [Indexed: 11/22/2022] Open
Abstract
Despite nearly 30 years of development and recent highlights of nitric oxide (NO) donors and NO delivery systems in anticancer therapy, the limited understanding of exogenous NO's effects on the immune system has prevented their advancement into clinical use. In particular, the effects of exogenously delivered NO differing from that of endogenous NO has obscured how the potential and functions of NO in anticancer therapy may be estimated and exploited despite the accumulating evidence of NO's cancer therapy-potentiating effects on the immune system. After introducing their fundamentals and characteristics, this review discusses the current mechanistic understanding of NO donors and delivery systems in modulating the immunogenicity of cancer cells as well as the differentiation and functions of innate and adaptive immune cells. Lastly, the potential for the complex modulatory effects of NO with the immune system to be leveraged for therapeutic applications is discussed in the context of recent advancements in the implementation of NO delivery systems for anticancer immunotherapy applications. SIGNIFICANCE STATEMENT: Despite a 30-year history and recent highlights of nitric oxide (NO) donors and delivery systems as anticancer therapeutics, their clinical translation has been limited. Increasing evidence of the complex interactions between NO and the immune system has revealed both the potential and hurdles in their clinical translation. This review summarizes the effects of exogenous NO on cancer and immune cells in vitro and elaborates these effects in the context of recent reports exploiting NO delivery systems in vivo in cancer therapy applications.
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Affiliation(s)
- Jihoon Kim
- Parker H. Petit Institute for Bioengineering and Bioscience (J.K., S.N.T.), George W. Woodruff School of Mechanical Engineering (J.K., S.N.T.), and Wallace H. Coulter Department of Biomedical Engineering (S.N.T.), Georgia Institute of Technology, Atlanta, Georgia; Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia (S.N.T.); and Division of Biological Science and Technology, Yonsei University, Wonju, South Korea (J.K.)
| | - Susan N Thomas
- Parker H. Petit Institute for Bioengineering and Bioscience (J.K., S.N.T.), George W. Woodruff School of Mechanical Engineering (J.K., S.N.T.), and Wallace H. Coulter Department of Biomedical Engineering (S.N.T.), Georgia Institute of Technology, Atlanta, Georgia; Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia (S.N.T.); and Division of Biological Science and Technology, Yonsei University, Wonju, South Korea (J.K.)
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7
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Sanati M, Aminyavari S, Afshari AR, Sahebkar A. Mechanistic insight into the role of metformin in Alzheimer's disease. Life Sci 2022; 291:120299. [PMID: 34999113 DOI: 10.1016/j.lfs.2021.120299] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 12/23/2021] [Accepted: 12/31/2021] [Indexed: 11/28/2022]
Abstract
Alzheimer's disease (AD), a type of dementia, is characterized by progressive memory decline and cognition impairment. Despite the considerable body of evidence regarding AD pathophysiology, current therapies merely slow down the disease progression, and a comprehensive therapeutic approach is unavailable. Accordingly, finding an efficient multifunctional remedy is necessary to blunt the increasing rate of AD incidence in the upcoming years. AD shares pathophysiological similarities (e.g., impairment of cognitive functions, insulin sensitivity, and brain glucose metabolism) with noninsulin-dependent diabetes mellitus (NIDDM), which offers the utilization of metformin, a biguanide hypoglycemic agent, as an alternative therapeutic approach in AD therapy. Emerging evidence has revealed the impact of metformin in patients suffering from AD. It has been described that metformin employs multiple mechanisms to improve cognition and memory impairment in pre-clinical AD models, including reduction of hippocampal amyloid-beta (Aβ) plaque and neurofibrillary tangles (NFTs) load, suppression of inflammation, amelioration of mitochondrial dysfunction and oxidative stress, restriction of apoptotic neuronal death, and induction of neurogenesis. This review discusses the pre-clinical evidence, which may shed light on the role of metformin in AD and provide a more comprehensive mechanistic insight for future studies in this area of research.
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Affiliation(s)
- Mehdi Sanati
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Birjand University of Medical Sciences, Birjand, Iran
| | - Samaneh Aminyavari
- Department of Neuroscience and Addiction Studies, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Amir R Afshari
- Department of Physiology and Pharmacology, Faculty of Medicine, North Khorasan University of Medical Sciences, Bojnurd, Iran
| | - Amirhossein Sahebkar
- Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran; Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran; School of Medicine, The University of Western Australia, Perth, Australia; Department of Biotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.
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8
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Lourenço CF, Laranjinha J. Nitric Oxide Pathways in Neurovascular Coupling Under Normal and Stress Conditions in the Brain: Strategies to Rescue Aberrant Coupling and Improve Cerebral Blood Flow. Front Physiol 2021; 12:729201. [PMID: 34744769 PMCID: PMC8569710 DOI: 10.3389/fphys.2021.729201] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 09/20/2021] [Indexed: 01/04/2023] Open
Abstract
The brain has impressive energy requirements and paradoxically, very limited energy reserves, implying its huge dependency on continuous blood supply. Aditionally, cerebral blood flow must be dynamically regulated to the areas of increased neuronal activity and thus, of increased metabolic demands. The coupling between neuronal activity and cerebral blood flow (CBF) is supported by a mechanism called neurovascular coupling (NVC). Among the several vasoactive molecules released by glutamatergic activation, nitric oxide (•NO) is recognized to be a key player in the process and essential for the development of the neurovascular response. Classically, •NO is produced in neurons upon the activation of the glutamatergic N-methyl-D-aspartate (NMDA) receptor by the neuronal isoform of nitric oxide synthase and promotes vasodilation by activating soluble guanylate cyclase in the smooth muscle cells of the adjacent arterioles. This pathway is part of a more complex network in which other molecular and cellular intervenients, as well as other sources of •NO, are involved. The elucidation of these interacting mechanisms is fundamental in understanding how the brain manages its energy requirements and how the failure of this process translates into neuronal dysfunction. Here, we aimed to provide an integrated and updated perspective of the role of •NO in the NVC, incorporating the most recent evidence that reinforces its central role in the process from both viewpoints, as a physiological mediator and a pathological stressor. First, we described the glutamate-NMDA receptor-nNOS axis as a central pathway in NVC, then we reviewed the link between the derailment of the NVC and neuronal dysfunction associated with neurodegeneration (with a focus on Alzheimer's disease). We further discussed the role of oxidative stress in the NVC dysfunction, specifically by decreasing the •NO bioavailability and diverting its bioactivity toward cytotoxicity. Finally, we highlighted some strategies targeting the rescue or maintenance of •NO bioavailability that could be explored to mitigate the NVC dysfunction associated with neurodegenerative conditions. In line with this, the potential modulatory effects of dietary nitrate and polyphenols on •NO-dependent NVC, in association with physical exercise, may be used as effective non-pharmacological strategies to promote the •NO bioavailability and to manage NVC dysfunction in neuropathological conditions.
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Affiliation(s)
- Cátia F Lourenço
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - João Laranjinha
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
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9
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Akther S, Hirase H. Assessment of astrocytes as a mediator of memory and learning in rodents. Glia 2021; 70:1484-1505. [PMID: 34582594 DOI: 10.1002/glia.24099] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 09/15/2021] [Accepted: 09/16/2021] [Indexed: 12/26/2022]
Abstract
The classical view of astrocytes is that they provide supportive functions for neurons, transporting metabolites and maintaining the homeostasis of the extracellular milieu. This view is gradually changing with the advent of molecular genetics and optical methods allowing interrogation of selected cell types in live experimental animals. An emerging view that astrocytes additionally act as a mediator of synaptic plasticity and contribute to learning processes has gained in vitro and in vivo experimental support. Here we focus on the literature published in the past two decades to review the roles of astrocytes in brain plasticity in rodents, whereby the roles of neurotransmitters and neuromodulators are considered to be comparable to those in humans. We outline established inputs and outputs of astrocytes and discuss how manipulations of astrocytes have impacted the behavior in various learning paradigms. Multiple studies suggest that the contribution of astrocytes has a considerably longer time course than neuronal activation, indicating metabolic roles of astrocytes. We advocate that exploring upstream and downstream mechanisms of astrocytic activation will further provide insight into brain plasticity and memory/learning impairment.
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Affiliation(s)
- Sonam Akther
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hajime Hirase
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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10
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ADORA 1-driven brain-sympathetic neuro-adipose connections control body weight and adipose lipid metabolism. Mol Psychiatry 2021; 26:2805-2819. [PMID: 33067580 PMCID: PMC8050129 DOI: 10.1038/s41380-020-00908-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 09/14/2020] [Accepted: 10/01/2020] [Indexed: 12/21/2022]
Abstract
It is essential to elucidate brain-adipocyte interactions in order to tackle obesity and its comorbidities, as the precise control of brain-adipose tissue cross-talk is crucial for energy and glucose homeostasis. Recent studies show that in the peripheral adipose tissue, adenosine induces adipogenesis through peripheral adenosine A1 receptor (pADORA1) signaling; however, it remains unclear whether systemic and adipose tissue metabolism would also be under the control of central (c) ADORA1 signaling. Here, we use tissue-specific pharmacology and metabolic tools to clarify the roles of cADORA1 signaling in energy and adipocyte physiology. We found that cADORA1 signaling reduces body weight while also inducing adipose tissue lipolysis. cADORA1 signaling also increases adipose tissue sympathetic norepinephrine content. In contrast, pADORA1 signaling facilitates a high-fat diet-induced obesity (DIO). We propose here a novel mechanism in which cADORA1 and pADORA1 signaling hinder and aggravate DIO, respectively.
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11
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Tellios V, Maksoud MJE, Xiang YY, Lu WY. Nitric Oxide Critically Regulates Purkinje Neuron Dendritic Development Through a Metabotropic Glutamate Receptor Type 1-Mediated Mechanism. THE CEREBELLUM 2021; 19:510-526. [PMID: 32270464 DOI: 10.1007/s12311-020-01125-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Nitric oxide (NO), specifically derived from neuronal nitric oxide synthase (nNOS), is a well-established regulator of synaptic transmission in Purkinje neurons (PNs), governing fundamental processes such as motor learning and coordination. Previous phenotypic analyses showed similar cerebellar structures between neuronal nitric oxide null (nNOS-/-) and wild-type (WT) adult male mice, despite prominent ataxic behavior within nNOS-/- mice. However, a study has yet to characterize PN molecular structure and their excitatory inputs during development in nNOS-/- mice. This study is the first to explore morphological abnormalities within the cerebellum of nNOS-/- mice, using immunohistochemistry and immunoblotting. This study sought to examine PN dendritic morphology and the expression of metabotropic glutamate receptor type 1 (mGluR1), vesicular glutamate transporter type 1 and 2 (vGluT1 and vGluT2), stromal interaction molecule 1 (STIM1), and calpain-1 within PNs of WT and nNOS-/- mice at postnatal day 7 (PD7), 2 weeks (2W), and 7 weeks (7W) of age. Results showed a decrease in PN dendritic branching at PD7 in nNOS-/- cerebella, while aberrant dendritic spine formation was noted in adult ages. Total protein expression of mGluR1 was decreased in nNOS-/- cerebella across development, while vGluT2, STIM1, and calpain-1 were significantly increased. Ex vivo treatment of WT slices with NOS inhibitor L-NAME increased calpain-1 expression, whereas treating nNOS-/- cerebellar slices with NO donor NOC-18 decreased calpain-1. Moreover, mGluR1 agonist DHPG increased calpain-1 in WT, but not in nNOS-/- slices. Together, these results indicate a novel role for nNOS/NO signaling in PN development, particularly by regulating an mGluR1-initiated calcium signaling mechanism.
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Affiliation(s)
- Vasiliki Tellios
- Graduate Program of Neuroscience, The University of Western Ontario, London, N6A 5B7, Canada.,Robarts Research Institute, London, N6A 5B7, Canada
| | - Matthew J E Maksoud
- Graduate Program of Neuroscience, The University of Western Ontario, London, N6A 5B7, Canada.,Robarts Research Institute, London, N6A 5B7, Canada
| | | | - Wei-Yang Lu
- Graduate Program of Neuroscience, The University of Western Ontario, London, N6A 5B7, Canada. .,Robarts Research Institute, London, N6A 5B7, Canada. .,Department of Physiology and Pharmacology, The University of Western Ontario, London, N6A 5B7, Canada.
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12
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Huang Z, Xie N, Illes P, Di Virgilio F, Ulrich H, Semyanov A, Verkhratsky A, Sperlagh B, Yu SG, Huang C, Tang Y. From purines to purinergic signalling: molecular functions and human diseases. Signal Transduct Target Ther 2021; 6:162. [PMID: 33907179 PMCID: PMC8079716 DOI: 10.1038/s41392-021-00553-z] [Citation(s) in RCA: 178] [Impact Index Per Article: 59.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 01/24/2021] [Accepted: 02/24/2021] [Indexed: 02/06/2023] Open
Abstract
Purines and their derivatives, most notably adenosine and ATP, are the key molecules controlling intracellular energy homoeostasis and nucleotide synthesis. Besides, these purines support, as chemical messengers, purinergic transmission throughout tissues and species. Purines act as endogenous ligands that bind to and activate plasmalemmal purinoceptors, which mediate extracellular communication referred to as "purinergic signalling". Purinergic signalling is cross-linked with other transmitter networks to coordinate numerous aspects of cell behaviour such as proliferation, differentiation, migration, apoptosis and other physiological processes critical for the proper function of organisms. Pathological deregulation of purinergic signalling contributes to various diseases including neurodegeneration, rheumatic immune diseases, inflammation, and cancer. Particularly, gout is one of the most prevalent purine-related disease caused by purine metabolism disorder and consequent hyperuricemia. Compelling evidence indicates that purinoceptors are potential therapeutic targets, with specific purinergic agonists and antagonists demonstrating prominent therapeutic potential. Furthermore, dietary and herbal interventions help to restore and balance purine metabolism, thus addressing the importance of a healthy lifestyle in the prevention and relief of human disorders. Profound understanding of molecular mechanisms of purinergic signalling provides new and exciting insights into the treatment of human diseases.
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Grants
- National Key R&D Program of China (2019YFC1709101,2020YFA0509400, 2020YFC2002705), the National Natural Science Foundation of China (81821002, 81790251, 81373735, 81972665), Guangdong Basic and Applied Basic Research Foundation (2019B030302012), the Project First-Class Disciplines Development of Chengdu University of Traditional Chinese Medicine (CZYHW1901), São Paulo Research Foundation (FAPESP 2018/07366-4), Russian Science Foundation grant 20-14-00241, NSFC-BFBR;and Science and Technology Program of Sichuan Province, China (2019YFH0108)
- National Key R&D Program of China (2020YFA0509400, 2020YFC2002705), the National Natural Science Foundation of China (81821002, 81790251).
- National Key R&D Program of China (2020YFA0509400, 2020YFC2002705), the National Natural Science Foundation of China (81821002, 81790251), Guangdong Basic and Applied Basic Research Foundation (2019B030302012).
- the Project First-Class Disciplines Development of Chengdu University of Traditional Chinese Medicine (CZYHW1901) and Science and Technology Program of Sichuan Province, China (2019YFH0108).
- the Project First-Class Disciplines Development of Chengdu University of Traditional Chinese Medicine (CZYHW1901), and Science and Technology Program of Sichuan Province, China (2019YFH0108).
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Affiliation(s)
- Zhao Huang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, and West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Na Xie
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, and West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Peter Illes
- International Collaborative Centre on Big Science Plan for Purinergic Signalling, Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Universitaet Leipzig, Leipzig, Germany
| | | | - Henning Ulrich
- International Collaborative Centre on Big Science Plan for Purinergic Signalling, Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | - Alexey Semyanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
- Sechenov First Moscow State Medical University, Moscow, Russia
| | - Alexei Verkhratsky
- International Collaborative Centre on Big Science Plan for Purinergic Signalling, Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Sechenov First Moscow State Medical University, Moscow, Russia
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Beata Sperlagh
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Shu-Guang Yu
- International Collaborative Centre on Big Science Plan for Purinergic Signalling, Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Acupuncture and Chronobiology Key Laboratory of Sichuan Province, Chengdu, China
| | - Canhua Huang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, and West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, China.
- School of Basic Medical Sciences, Chengdu University of Traditional Chinese Medicine, Chengdu, China.
| | - Yong Tang
- International Collaborative Centre on Big Science Plan for Purinergic Signalling, Chengdu University of Traditional Chinese Medicine, Chengdu, China.
- Acupuncture and Chronobiology Key Laboratory of Sichuan Province, Chengdu, China.
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13
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Institoris A, Murphy-Royal C, Tarantini S, Yabluchanskiy A, Haidey JN, Csiszar A, Ungvari Z, Gordon GR. Whole brain irradiation in mice causes long-term impairment in astrocytic calcium signaling but preserves astrocyte-astrocyte coupling. GeroScience 2021; 43:197-212. [PMID: 33094399 PMCID: PMC8050172 DOI: 10.1007/s11357-020-00289-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 10/14/2020] [Indexed: 11/29/2022] Open
Abstract
Whole brain irradiation (WBI) therapy is an important treatment for brain metastases and potential microscopic malignancies. WBI promotes progressive cognitive dysfunction in over half of surviving patients, yet, the underlying mechanisms remain obscure. Astrocytes play critical roles in the regulation of neuronal activity, brain metabolism, and cerebral blood flow, and while neurons are considered radioresistant, astrocytes are sensitive to γ-irradiation. Hallmarks of astrocyte function are the ability to generate stimulus-induced intercellular Ca2+ signals and to move metabolic substrates through the connected astrocyte network. We tested the hypothesis that WBI-induced cognitive impairment associates with persistent impairment of astrocytic Ca2+ signaling and/or gap junctional coupling. Mice were subjected to a clinically relevant protocol of fractionated WBI, and 12 to 15 months after irradiation, we confirmed persistent cognitive impairment compared to controls. To test the integrity of astrocyte-to-astrocyte gap junctional coupling postWBI, astrocytes were loaded with Alexa-488-hydrazide by patch-based dye infusion, and the increase of fluorescence signal in neighboring astrocyte cell bodies was assessed with 2-photon microscopy in acute slices of the sensory-motor cortex. We found that WBI did not affect astrocyte-to-astrocyte gap junctional coupling. Astrocytic Ca2+ responses induced by bath administration of phenylephrine (detected with Rhod-2/AM) were also unaltered by WBI. However, an electrical stimulation protocol used in long-term potentiation (theta burst), revealed attenuated astrocyte Ca2+ responses in the astrocyte arbor and soma in WBI. Our data show that WBI causes a long-lasting decrement in synaptic-evoked astrocyte Ca2+ signals 12-15 months postirradiation, which may be an important contributor to cognitive decline seen after WBI.
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Affiliation(s)
- Adam Institoris
- Department of Physiology and Pharmacology, Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Ciaran Murphy-Royal
- Department of Physiology and Pharmacology, Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Stefano Tarantini
- Department of Biochemistry and Molecular Biology, Vascular Cognitive Impairment and Neurodegeneration Program, Reynolds Oklahoma Center on Aging/Oklahoma Center for Geroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary
| | - Andriy Yabluchanskiy
- Department of Biochemistry and Molecular Biology, Vascular Cognitive Impairment and Neurodegeneration Program, Reynolds Oklahoma Center on Aging/Oklahoma Center for Geroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Jordan N Haidey
- Department of Physiology and Pharmacology, Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Anna Csiszar
- Department of Biochemistry and Molecular Biology, Vascular Cognitive Impairment and Neurodegeneration Program, Reynolds Oklahoma Center on Aging/Oklahoma Center for Geroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Zoltan Ungvari
- Department of Biochemistry and Molecular Biology, Vascular Cognitive Impairment and Neurodegeneration Program, Reynolds Oklahoma Center on Aging/Oklahoma Center for Geroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary
| | - Grant R Gordon
- Department of Physiology and Pharmacology, Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.
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14
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Tewari D, Sah AN, Bawari S, Nabavi SF, Dehpour AR, Shirooie S, Braidy N, Fiebich BL, Vacca RA, Nabavi SM. Role of Nitric Oxide in Neurodegeneration: Function, Regulation, and Inhibition. Curr Neuropharmacol 2020; 19:114-126. [PMID: 32348225 PMCID: PMC8033982 DOI: 10.2174/1570159x18666200429001549] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 03/17/2020] [Accepted: 04/24/2020] [Indexed: 12/14/2022] Open
Abstract
Reactive nitrogen species (RNS) and reactive oxygen species (ROS), collectively known as reactive oxygen and nitrogen species (RONS), are the products of normal cellular metabolism and interact with several vital biomolecules including nucleic acid, proteins, and membrane lipids and alter their function in an irreversible manner which can lead to cell death. There is an imperative role for oxidative stress in the pathogenesis of cognitive impairments and the development and progression of neural injury. Elevated production of higher amounts of nitric oxide (NO) takes place in numerous pathological conditions, such as neurodegenerative diseases, inflammation, and ischemia, which occur concurrently with elevated nitrosative/oxidative stress. The enzyme nitric oxide synthase (NOS) is responsible for the generation of NO in different cells by conversion of L-arginine (Arg) to L-citrulline. Therefore, the NO signaling pathway represents a viable therapeutic target. Naturally occurring polyphenols targeting the NO signaling pathway can be of major importance in the field of neurodegeneration and related complications. Here, we comprehensively review the importance of NO and its production in the human body and afterwards highlight the importance of various natural products along with their mechanisms against various neurodegenerative diseases involving their effect on NO production.
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Affiliation(s)
- Devesh Tewari
- Department of Pharmacognosy, School of Pharmaceutical Sciences, Lovely Professional University, Phagwara, Punjab, 144411, India
| | - Archana N Sah
- Department of Pharmaceutical Sciences, Faculty of Technology, Bhimtal Campus, Kumaun University, Nainital, Uttarakhand 263136, India
| | - Sweta Bawari
- School of Pharmacy, Sharda University, Knowledge Park-III, Greater Noida, Uttar Pradesh, 201310, India
| | - Seyed F Nabavi
- Applied Biotechnology Research Center, Baqiyatallah University of Medical Sciences, Tehran 1435916471, Iran
| | - Ahmad R Dehpour
- Department of Pharmacology, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Samira Shirooie
- Pharmaceutical Sciences Research Center, Health Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Nady Braidy
- Centre for Healthy Brain Ageing, School of Psychiatry, University of New South Wales, Australia
| | - Bernd L Fiebich
- Neuroimmunology and Neurochemistry Research Group, Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Rosa A Vacca
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, National Council of Research, Bari, Italy
| | - Seyed M Nabavi
- Applied Biotechnology Research Center, Baqiyatallah University of Medical Sciences, Tehran 1435916471, Iran
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15
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Kaur N, Chugh H, Sakharkar MK, Dhawan U, Chidambaram SB, Chandra R. Neuroinflammation Mechanisms and Phytotherapeutic Intervention: A Systematic Review. ACS Chem Neurosci 2020; 11:3707-3731. [PMID: 33146995 DOI: 10.1021/acschemneuro.0c00427] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Neuroinflammation is indicated in the pathogenesis of several acute and chronic neurological disorders. Acute lesions in the brain parenchyma induce intense and highly complex neuroinflammatory reactions with similar mechanisms among various disease prototypes. Microglial cells in the CNS sense tissue damage and initiate inflammatory responses. The cellular and humoral constituents of the neuroinflammatory reaction to brain injury contribute significantly to secondary brain damage and neurodegeneration. Inflammatory cascades such as proinflammatory cytokines from invading leukocytes and direct cell-mediated cytotoxicity between lymphocytes and neurons are known to cause "collateral damage" in models of acute brain injury. In addition to degeneration and neuronal cell loss, there are secondary inflammatory mechanisms that modulate neuronal activity and affect neuroinflammation which can even be detected at the behavioral level. Hence, several of health conditions result from these pathogenetic conditions which are underlined by progressive neuronal function loss due to chronic inflammation and oxidative stress. In the first part of this Review, we discuss critical neuroinflammatory mediators and their pathways in detail. In the second part, we review the phytochemicals which are considered as potential therapeutic molecules for treating neurodegenerative diseases with an inflammatory component.
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Affiliation(s)
- Navrinder Kaur
- Drug Discovery and Development Laboratory, Department of Chemistry, University of Delhi, New Delhi-110007, India
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, New Delhi-110007, India
| | - Heerak Chugh
- Drug Discovery and Development Laboratory, Department of Chemistry, University of Delhi, New Delhi-110007, India
| | - Meena K. Sakharkar
- College of Pharmacy and Nutrition, University of Sasketchwan, Saskatoon S7N 5E5, Canada
| | - Uma Dhawan
- Department of Biomedical Science, Bhaskaracharya College of Applied Sciences, University of Delhi, New Delhi-110075, India
| | - Saravana Babu Chidambaram
- Department of Pharmacology, JSS College of Pharmacy, JSS Academy of Higher Education & Research (JSS AHER), S.S. Nagar, Mysuru-570015, India
- Centre for Experimental Pharmacology and Toxicology (CPT), JSS Academy of Higher Education & Research JSS AHER, Mysuru-570015, India
| | - Ramesh Chandra
- Drug Discovery and Development Laboratory, Department of Chemistry, University of Delhi, New Delhi-110007, India
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, New Delhi-110007, India
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16
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Tedoldi A, Argent L, Montgomery JM. The role of the tripartite synapse in the heart: how glial cells may contribute to the physiology and pathophysiology of the intracardiac nervous system. Am J Physiol Cell Physiol 2020; 320:C1-C14. [PMID: 33085497 DOI: 10.1152/ajpcell.00363.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
One of the major roles of the intracardiac nervous system (ICNS) is to act as the final site of signal integration for efferent information destined for the myocardium to enable local control of heart rate and rhythm. Multiple subtypes of neurons exist in the ICNS where they are organized into clusters termed ganglionated plexi (GP). The majority of cells in the ICNS are actually glial cells; however, despite this, ICNS glial cells have received little attention to date. In the central nervous system, where glial cell function has been widely studied, glia are no longer viewed simply as supportive cells but rather have been shown to play an active role in modulating neuronal excitability and synaptic plasticity. Pioneering studies have demonstrated that in addition to glia within the brain stem, glial cells within multiple autonomic ganglia in the peripheral nervous system, including the ICNS, can also act to modulate cardiovascular function. Clinically, patients with atrial fibrillation (AF) undergoing catheter ablation show high plasma levels of S100B, a protein produced by cardiac glial cells, correlated with decreased AF recurrence. Interestingly, S100B also alters GP neuron excitability and neurite outgrowth in the ICNS. These studies highlight the importance of understanding how glial cells can affect the heart by modulating GP neuron activity or synaptic inputs. Here, we review studies investigating glia both in the central and peripheral nervous systems to discuss the potential role of glia in controlling cardiac function in health and disease, paying particular attention to the glial cells of the ICNS.
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Affiliation(s)
- Angelo Tedoldi
- Department of Physiology, University of Auckland, Auckland, New Zealand.,Manaaki Mānawa Centre for Heart Research, University of Auckland, Auckland, New Zealand
| | - Liam Argent
- Department of Physiology, University of Auckland, Auckland, New Zealand.,Manaaki Mānawa Centre for Heart Research, University of Auckland, Auckland, New Zealand
| | - Johanna M Montgomery
- Department of Physiology, University of Auckland, Auckland, New Zealand.,Manaaki Mānawa Centre for Heart Research, University of Auckland, Auckland, New Zealand
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17
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Purinergic signaling orchestrating neuron-glia communication. Pharmacol Res 2020; 162:105253. [PMID: 33080321 DOI: 10.1016/j.phrs.2020.105253] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 09/29/2020] [Accepted: 10/09/2020] [Indexed: 12/12/2022]
Abstract
This review discusses the evidence supporting a role for ATP signaling (operated by P2X and P2Y receptors) and adenosine signaling (mainly operated by A1 and A2A receptors) in the crosstalk between neurons, astrocytes, microglia and oligodendrocytes. An initial emphasis will be given to the cooperation between adenosine receptors to sharpen information salience encoding across synapses. The interplay between ATP and adenosine signaling in the communication between astrocytes and neurons will then be presented in context of the integrative properties of the astrocytic syncytium, allowing to implement heterosynaptic depression processes in neuronal networks. The process of microglia 'activation' and its control by astrocytes and neurons will then be analyzed under the perspective of an interplay between different P2 receptors and adenosine A2A receptors. In spite of these indications of a prominent role of purinergic signaling in the bidirectional communication between neurons and glia, its therapeutical exploitation still awaits obtaining an integrated view of the spatio-temporal action of ATP signaling and adenosine signaling, clearly distinguishing the involvement of both purinergic signaling systems in the regulation of physiological processes and in the control of pathogenic-like responses upon brain dysfunction or damage.
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18
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Subauste CS. The CD40-ATP-P2X 7 Receptor Pathway: Cell to Cell Cross-Talk to Promote Inflammation and Programmed Cell Death of Endothelial Cells. Front Immunol 2019; 10:2958. [PMID: 31921199 PMCID: PMC6928124 DOI: 10.3389/fimmu.2019.02958] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 12/02/2019] [Indexed: 12/15/2022] Open
Abstract
Extracellular adenosine 5′-triphosphate (ATP) functions not only as a neurotransmitter but is also released by non-excitable cells and mediates cell–cell communication involving glia. In pathological conditions, extracellular ATP released by astrocytes may act as a “danger” signal that activates microglia and promotes neuroinflammation. This review summarizes in vitro and in vivo studies that identified CD40 as a novel trigger of ATP release and purinergic-induced inflammation. The use of transgenic mice with expression of CD40 restricted to retinal Müller glia and a model of diabetic retinopathy (a disease where the CD40 pathway is activated) established that CD40 induces release of ATP in Müller glia and triggers in microglia/macrophages purinergic receptor-dependent inflammatory responses that drive the development of retinopathy. The CD40-ATP-P2X7 pathway not only amplifies inflammation but also induces death of retinal endothelial cells, an event key to the development of capillary degeneration and retinal ischemia. Taken together, CD40 expressed in non-hematopoietic cells is sufficient to mediate inflammation and tissue pathology as well as cause death of retinal endothelial cells. This process likely contributes to development of degenerate capillaries, a hallmark of diabetic and ischemic retinopathies. Blockade of signaling pathways downstream of CD40 operative in non-hematopoietic cells may offer a novel means of treating diabetic and ischemic retinopathies.
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Affiliation(s)
- Carlos S Subauste
- Division of Infectious Diseases and HIV Medicine, Department of Medicine, Case Western Reserve University, Cleveland, OH, United States.,Department of Pathology, Case Western Reserve University, Cleveland, OH, United States
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19
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Vardjan N, Parpura V, Verkhratsky A, Zorec R. Gliocrine System: Astroglia as Secretory Cells of the CNS. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1175:93-115. [PMID: 31583585 DOI: 10.1007/978-981-13-9913-8_4] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Astrocytes are secretory cells, actively participating in cell-to-cell communication in the central nervous system (CNS). They sense signaling molecules in the extracellular space, around the nearby synapses and also those released at much farther locations in the CNS, by their cell surface receptors, get excited to then release their own signaling molecules. This contributes to the brain information processing, based on diffusion within the extracellular space around the synapses and on convection when locales relatively far away from the release sites are involved. These functions resemble secretion from endocrine cells, therefore astrocytes were termed to be a part of the gliocrine system in 2015. An important mechanism, by which astrocytes release signaling molecules is the merger of the vesicle membrane with the plasmalemma, i.e., exocytosis. Signaling molecules stored in astroglial secretory vesicles can be discharged into the extracellular space after the vesicle membrane fuses with the plasma membrane. This leads to a fusion pore formation, a channel that must widen to allow the exit of the Vesiclal cargo. Upon complete vesicle membrane fusion, this process also integrates other proteins, such as receptors, transporters and channels into the plasma membrane, determining astroglial surface signaling landscape. Vesiclal cargo, together with the whole vesicle can also exit astrocytes by the fusion of multivesicular bodies with the plasma membrane (exosomes) or by budding of vesicles (ectosomes) from the plasma membrane into the extracellular space. These astroglia-derived extracellular vesicles can later interact with various target cells. Here, the characteristics of four types of astroglial secretory vesicles: synaptic-like microvesicles, dense-core vesicles, secretory lysosomes, and extracellular vesicles, are discussed. Then machinery for vesicle-based exocytosis, second messenger regulation and the kinetics of exocytotic vesicle content discharge or release of extracellular vesicles are considered. In comparison to rapidly responsive, electrically excitable neurons, the receptor-mediated cytosolic excitability-mediated astroglial exocytotic vesicle-based transmitter release is a relatively slow process.
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Affiliation(s)
- Nina Vardjan
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, 1000, Ljubljana, Slovenia. .,Celica Biomedical, 1000, Ljubljana, Slovenia.
| | - Vladimir Parpura
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK.,Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark.,Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain
| | - Robert Zorec
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, 1000, Ljubljana, Slovenia. .,Celica Biomedical, 1000, Ljubljana, Slovenia.
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20
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Guo LY, Lozinski B, Yong VW. Exercise in multiple sclerosis and its models: Focus on the central nervous system outcomes. J Neurosci Res 2019; 98:509-523. [DOI: 10.1002/jnr.24524] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/17/2019] [Accepted: 08/21/2019] [Indexed: 12/30/2022]
Affiliation(s)
- Ling Yi Guo
- Department of Physiology and Pharmacology Western University London Ontario Canada
- Hotchkiss Brain InstituteUniversity of Calgary Calgary Alberta Canada
- Department of Clinical Neurosciences University of Calgary Calgary Alberta Canada
| | - Brian Lozinski
- Hotchkiss Brain InstituteUniversity of Calgary Calgary Alberta Canada
- Department of Clinical Neurosciences University of Calgary Calgary Alberta Canada
| | - Voon Wee Yong
- Hotchkiss Brain InstituteUniversity of Calgary Calgary Alberta Canada
- Department of Clinical Neurosciences University of Calgary Calgary Alberta Canada
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21
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Velasco-Estevez M, Rolle SO, Mampay M, Dev KK, Sheridan GK. Piezo1 regulates calcium oscillations and cytokine release from astrocytes. Glia 2019; 68:145-160. [PMID: 31433095 DOI: 10.1002/glia.23709] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 07/16/2019] [Accepted: 08/07/2019] [Indexed: 12/11/2022]
Abstract
Astrocytes are important for information processing in the brain and they achieve this by fine-tuning neuronal communication via continuous uptake and release of biochemical modulators of neurotransmission and synaptic plasticity. Often overlooked are their important functions in mechanosensation. Indeed, astrocytes can detect pathophysiological changes in the mechanical properties of injured, ageing, or degenerating brain tissue. We have recently shown that astrocytes surrounding mechanically-stiff amyloid plaques upregulate the mechanosensitive ion channel, Piezo1. Moreover, ageing transgenic Alzheimer's rats harboring a chronic peripheral bacterial infection displayed enhanced Piezo1 expression in amyloid plaque-reactive astrocytes of the hippocampus and cerebral cortex. Here, we have shown that the bacterial endotoxin, lipopolysaccharide (LPS), also upregulates Piezo1 in primary mouse cortical astrocyte cultures in vitro. Activation of Piezo1, via the small molecule agonist Yoda1, enhanced Ca2+ influx in both control and LPS-stimulated astrocytes. Moreover, Yoda1 augmented intracellular Ca2+ oscillations but decreased subsequent Ca2+ influx in response to adenosine triphosphate (ATP) stimulation. Neither blocking nor activating Piezo1 affected cell viability. However, LPS-stimulated astrocyte cultures exposed to the Piezo1 activator, Yoda1, migrated significantly slower than reactive astrocytes treated with the mechanosensitive channel-blocking peptide, GsMTx4. Furthermore, our data show that activating Piezo1 channels inhibits the release of cytokines and chemokines, such as IL-1β, TNFα, and fractalkine (CX3 CL1), from LPS-stimulated astrocyte cultures. Taken together, our results suggest that astrocytic Piezo1 upregulation may act to dampen neuroinflammation and could be a useful drug target for neuroinflammatory disorders of the brain.
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Affiliation(s)
- María Velasco-Estevez
- Drug Development, Department of Physiology, School of Medicine, Trinity College Dublin, Dublin, Ireland
| | - Sara O Rolle
- Department of Bioengineering, Imperial College London, London, UK.,Francis Crick Institute, London, UK
| | - Myrthe Mampay
- School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, UK
| | - Kumlesh K Dev
- Drug Development, Department of Physiology, School of Medicine, Trinity College Dublin, Dublin, Ireland
| | - Graham K Sheridan
- School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, UK.,School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, UK
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22
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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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23
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Santos-Cancel M, Simpson LW, Leach JB, White RJ. Direct, Real-Time Detection of Adenosine Triphosphate Release from Astrocytes in Three-Dimensional Culture Using an Integrated Electrochemical Aptamer-Based Sensor. ACS Chem Neurosci 2019; 10:2070-2079. [PMID: 30754968 PMCID: PMC6469990 DOI: 10.1021/acschemneuro.9b00033] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
In this manuscript, we describe the development and application of electrochemical aptamer-based (E-AB) sensors directly interfaced with astrocytes in three-dimensional (3D) cell culture to monitor stimulated release of adenosine triphosphate (ATP). The aptamer-based sensor couples specific detection of ATP, selective performance directly in cell culture media, and seconds time resolution using squarewave voltammetry for quantitative ATP-release measurements. More specifically, we demonstrate the ability to quantitatively monitor ATP release into the extracellular environment after stimulation by the addition of calcium (Ca2+), ionomycin, and glutamate. The sensor response is confirmed to be specific to ATP and requires the presence of astrocytes in culture. For example, PC12 cells do not elicit a sensor response after stimulation with the same stimulants. In addition, we confirmed cell viability in the collagen matrix for all conditions tested. Our hydrogel-sensor interface offers the potential to study the release of small molecule messengers in 3D environments. Given the generality of electrochemical aptamer-based sensors and the demonstrated successful interfacing of sensors with tissue scaffold material, in the long term, we anticipate our sensors will be able to translate from in vitro to in vivo small molecule recordings.
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Affiliation(s)
| | - Laura W. Simpson
- Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County, Baltimore, MD, USA
| | - Jennie B. Leach
- Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County, Baltimore, MD, USA
| | - Ryan J. White
- Department of Chemistry, University of Cincinnati, Cincinnati, OH, USA
- Department of Electrical Engineering and Computer Science, University of Cincinnati, Cincinnati, OH, USA
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24
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Elorza-Vidal X, Gaitán-Peñas H, Estévez R. Chloride Channels in Astrocytes: Structure, Roles in Brain Homeostasis and Implications in Disease. Int J Mol Sci 2019; 20:ijms20051034. [PMID: 30818802 PMCID: PMC6429410 DOI: 10.3390/ijms20051034] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 02/15/2019] [Accepted: 02/17/2019] [Indexed: 12/29/2022] Open
Abstract
Astrocytes are the most abundant cell type in the CNS (central nervous system). They exert multiple functions during development and in the adult CNS that are essential for brain homeostasis. Both cation and anion channel activities have been identified in astrocytes and it is believed that they play key roles in astrocyte function. Whereas the proteins and the physiological roles assigned to cation channels are becoming very clear, the study of astrocytic chloride channels is in its early stages. In recent years, we have moved from the identification of chloride channel activities present in astrocyte primary culture to the identification of the proteins involved in these activities, the determination of their 3D structure and attempts to gain insights about their physiological role. Here, we review the recent findings related to the main chloride channels identified in astrocytes: the voltage-dependent ClC-2, the calcium-activated bestrophin, the volume-activated VRAC (volume-regulated anion channel) and the stress-activated Maxi-Cl−. We discuss key aspects of channel biophysics and structure with a focus on their role in glial physiology and human disease.
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Affiliation(s)
- Xabier Elorza-Vidal
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes Disease and Therapy Program IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, 08907 Barcelona, Spain.
- Centro de Investigación en red de enfermedades raras (CIBERER), ISCIII, 08907 Barcelona, Spain.
| | - Héctor Gaitán-Peñas
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes Disease and Therapy Program IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, 08907 Barcelona, Spain.
- Centro de Investigación en red de enfermedades raras (CIBERER), ISCIII, 08907 Barcelona, Spain.
| | - Raúl Estévez
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes Disease and Therapy Program IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, 08907 Barcelona, Spain.
- Centro de Investigación en red de enfermedades raras (CIBERER), ISCIII, 08907 Barcelona, Spain.
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25
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Yang Q, Zhou J. Neuroinflammation in the central nervous system: Symphony of glial cells. Glia 2018; 67:1017-1035. [DOI: 10.1002/glia.23571] [Citation(s) in RCA: 160] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 10/26/2018] [Accepted: 11/02/2018] [Indexed: 12/19/2022]
Affiliation(s)
- Qiao‐qiao Yang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology Chinese Academy of Sciences Shanghai China
| | - Jia‐wei Zhou
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology Chinese Academy of Sciences Shanghai China
- University of Chinese Academy of Sciences Shanghai 200031 China
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Scofield MD. Exploring the Role of Astroglial Glutamate Release and Association With Synapses in Neuronal Function and Behavior. Biol Psychiatry 2018; 84:778-786. [PMID: 29258653 PMCID: PMC5948108 DOI: 10.1016/j.biopsych.2017.10.029] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 10/18/2017] [Accepted: 10/31/2017] [Indexed: 12/25/2022]
Abstract
Astrocytes are stellate cells whose appearance can resemble a pointed star, especially when visualizing glial fibrillary acidic protein, a canonical marker for astrocytes. Accordingly, there is a commonly made connection between the points of light that shine in the night sky and the diffuse and abundant cells that buffer ions and provide support for neurons. An exceptional amount of function has been attributed to, negated for, and potentially reaffirmed for these cells, especially regarding their ability to release neuroactive molecules and influence synaptic plasticity. This makes the precise role of astrocytes in tuning neural communication seem difficult to grasp. However, data from animal models of addiction demonstrate that a variety of drug-induced molecular adaptations responsible for relapse vulnerability take place in astrocyte systems that regulate glutamate uptake and release. These findings highlight astrocytes as a critical component of the neural systems responsible for addiction, serving as a key component of the plasticity responsible for relapse and drug seeking. Here I assemble recent findings that utilize genetic tools to selectively manipulate or measure flux of internal calcium in astrocytes, focusing on G protein-coupled receptor-mediated mobilization of calcium and the induction of glutamate release. Further, I compile evidence regarding astrocyte glutamate release as well as astrocyte association with synapses with respect to the impact of these cellular phenomena in shaping synaptic transmission. I also place these findings in the context of the previous studies of Scofield et al., who explored the role of astrocytes in the nucleus accumbens in the neural mechanisms underlying cocaine seeking.
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Affiliation(s)
- Michael D. Scofield
- Department of Anesthesiology and Perioperative Medicine, Medical University of South Carolina, Charleston, SC, 29425 USA,Department of Neuroscience, Medical University of South Carolina, Charleston, SC, 29425 USA
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27
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Tran CHT, Peringod G, Gordon GR. Astrocytes Integrate Behavioral State and Vascular Signals during Functional Hyperemia. Neuron 2018; 100:1133-1148.e3. [PMID: 30482689 DOI: 10.1016/j.neuron.2018.09.045] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 06/25/2018] [Accepted: 09/24/2018] [Indexed: 01/17/2023]
Abstract
Dynamic changes in astrocyte free Ca2+ regulate synaptic signaling and local blood flow. Although astrocytes are poised to integrate signals from synapses and the vasculature to perform their functional roles, it remains unclear what dictates astrocyte responses during neurovascular coupling under realistic conditions. We examined peri-arteriole and peri-capillary astrocytes in the barrel cortex of active mice in response to sensory stimulation or volitional behaviors. We observed an AMPA and NMDA receptor-dependent elevation in astrocyte endfoot Ca2+ that followed functional hyperemia onset. This delayed astrocyte Ca2+ signal was dependent on the animal's action at the time of measurement as well as a neurovascular pathway that linked to endothelial-derived nitric oxide. A similar elevation in endfoot Ca2+ was evoked using vascular chemogenetics or optogenetics, and opto-stimulated dilation recruited the same nitric oxide pathway as functional hyperemia. These data show that behavioral state and microvasculature influence astrocyte Ca2+ in active mice. VIDEO ABSTRACT.
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Affiliation(s)
- Cam Ha T Tran
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Govind Peringod
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Grant R Gordon
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada.
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28
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Ganapathy K, Datta I, Bhonde R. Astrocyte-Like Cells Differentiated from Dental Pulp Stem Cells Protect Dopaminergic Neurons Against 6-Hydroxydopamine Toxicity. Mol Neurobiol 2018; 56:4395-4413. [PMID: 30327976 DOI: 10.1007/s12035-018-1367-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 09/25/2018] [Indexed: 12/20/2022]
Abstract
Dental pulp stem cells (DPSCs) are promising for use in neurodegenerative-diseases because of their neural crest origin. While neuronal differentiation of DPSCs has been shown, their plasticity towards astrocyte-like cells remains to be studied. We aimed to examine differentiation potential of DPSCs to astrocytes and their consequent neuroprotective role towards dopaminergic (DA) neurons under 6-hydroxydopamine (6-OHDA) toxicity. Induction of DPSCs to astrocytes with differentiation factors showed definitive increase in astrocyte-specific markers glial fibrillary acidic protein (GFAP), and excitatory amino acid transporter 2 along with glial calcium-binding protein S100β through FACS and immunofluorescence assays. RT-PCR and ELISA showed significant increase in BDNF and GDNF expression and secretion in astrocyte-differentiated DPSCs over naïve DPSCs. Neuroprotective role of these cells on DA neurons under 6-OHDA stress was evaluated by both contact and non-contact methods. FACS analysis of PKH26-stained SH-SY5Y homogenous cells in contact method and of TH immunopositive cells in primary midbrain culture in non-contact method both indicated higher survival of DA neurons in astrocyte-differentiated DPSCs over naïve DPSCs. Recovery of β-tubulin III and TH immunopositive cells was reduced in the presence of TrkB inhibitor, suggesting a key neuroprotective role of BDNF secretion by DPSCs. When nitric oxide (NO) release was inhibited by L-NAME in primary midbrain culture, BDNF release in co-culture under 6-OHDA stress reduced further in naïve DPSCs than in astrocyte-differentiated DPSCs, suggesting that BDNF release in naïve DPSCs is primarily regulated by paracrine signaling while for differentiated DPSCs, it is equally through autocrine and paracrine signaling with NO being the mediator. In conclusion, we suggest that DPSCs exposed to glial commitment cues exhibit substantial differentiation towards astrocyte-like cells with better neuroprotective activity against 6-OHDA toxicity than naïve DPSCs.
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Affiliation(s)
- Kavina Ganapathy
- Department of Biophysics, National Institute of Mental Health and Neurosciences, P.B. No - 2900, Hosur Road, Bengaluru, Karnataka, 560029, India.,School of Regenerative Medicine, Manipal University, Bengaluru, Karnataka, 560065, India
| | - Indrani Datta
- Department of Biophysics, National Institute of Mental Health and Neurosciences, P.B. No - 2900, Hosur Road, Bengaluru, Karnataka, 560029, India.
| | - Ramesh Bhonde
- School of Regenerative Medicine, Manipal University, Bengaluru, Karnataka, 560065, India.,Dr. D. Y. Patil Vidyapeeth, Pimpri, Pune, Maharashtra, 411018, India
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Osipova ED, Semyachkina-Glushkovskaya OV, Morgun AV, Pisareva NV, Malinovskaya NA, Boitsova EB, Pozhilenkova EA, Belova OA, Salmin VV, Taranushenko TE, Noda M, Salmina AB. Gliotransmitters and cytokines in the control of blood-brain barrier permeability. Rev Neurosci 2018; 29:567-591. [DOI: 10.1515/revneuro-2017-0092] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 11/26/2017] [Indexed: 11/15/2022]
Abstract
AbstractThe contribution of astrocytes and microglia to the regulation of neuroplasticity or neurovascular unit (NVU) is based on the coordinated secretion of gliotransmitters and cytokines and the release and uptake of metabolites. Blood-brain barrier (BBB) integrity and angiogenesis are influenced by perivascular cells contacting with the abluminal side of brain microvessel endothelial cells (pericytes, astrocytes) or by immune cells existing (microglia) or invading the NVU (macrophages) under pathologic conditions. The release of gliotransmitters or cytokines by activated astroglial and microglial cells is provided by distinct mechanisms, affects intercellular communication, and results in the establishment of microenvironment controlling BBB permeability and neuroinflammation. Glial glutamate transporters and connexin and pannexin hemichannels working in the tight functional coupling with the purinergic system serve as promising molecular targets for manipulating the intercellular communications that control BBB permeability in brain pathologies associated with excessive angiogenesis, cerebrovascular remodeling, and BBB-mediated neuroinflammation. Substantial progress in deciphering the molecular mechanisms underlying the (patho)physiology of perivascular glia provides promising approaches to novel clinically relevant therapies for brain disorders. The present review summarizes the current understandings on the secretory machinery expressed in glial cells (glutamate transporters, connexin and pannexin hemichannels, exocytosis mechanisms, membrane-derived microvesicles, and inflammasomes) and the role of secreted gliotransmitters and cytokines in the regulation of NVU and BBB permeability in (patho)physiologic conditions.
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Glutamate Induces Blood-Brain Barrier Permeability through Activation of N-Methyl-D-Aspartate Receptors. J Neurosci 2018; 36:12296-12298. [PMID: 27927949 DOI: 10.1523/jneurosci.2962-16.2016] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 10/25/2016] [Accepted: 10/26/2016] [Indexed: 11/21/2022] Open
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31
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Expression and Purification of Quinine Dihydro Pteridine Reductase from astrocytes and its significance in the astrocyte pathology. Int J Biol Macromol 2018; 110:567-572. [PMID: 29355631 DOI: 10.1016/j.ijbiomac.2018.01.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 12/11/2017] [Accepted: 01/01/2018] [Indexed: 11/23/2022]
Abstract
Quinine dihydropteridinereductase (QDPR) is involved in the synthesis of tetradihydrobiopteridine (BH4) that serve as cofactor for many aromatic hydroxylases including induced nitric oxide synthase (NOS) leading to NO production. Increased activity of QDPR has been associated with decrease levels of TGF-β, a cytokine that regulates the immune response and that elevated levels of NO has been associated with neurodegenerative diseases. Thus, expression of QDPR in astrocytes is essential to study the pathological changes observed in many neurodegenerative disorders. We have expressed QDPR in astrocytes and generated stably expressing clones that overexpresses QDPR. We further verified the specificity of QDPR expression using immunofluorescence and immunoblotting. To further confirm, we purified QDPR using Ni-NTA column and subjected the purified fraction to immunoblotting using anti-QDPR antibody and identified two major protein products of QDPR resolving at 25 and 17 kDa as reported in the literature. In order to further assess the significance of QDPR expression, we verified the expression of iNOS in QDPR over expressing cells. We show for the first time statistically significant up regulation of iNOS in QDPR overexpressing astrocytes. Increased expression of iNOS associated with astrocyte pathology seen in many neurodegenerative disorders may have implications in autoimmune neurodegenerative disorders.
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32
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Fricker M, Tolkovsky AM, Borutaite V, Coleman M, Brown GC. Neuronal Cell Death. Physiol Rev 2018; 98:813-880. [PMID: 29488822 PMCID: PMC5966715 DOI: 10.1152/physrev.00011.2017] [Citation(s) in RCA: 674] [Impact Index Per Article: 112.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 05/23/2017] [Accepted: 07/10/2017] [Indexed: 02/07/2023] Open
Abstract
Neuronal cell death occurs extensively during development and pathology, where it is especially important because of the limited capacity of adult neurons to proliferate or be replaced. The concept of cell death used to be simple as there were just two or three types, so we just had to work out which type was involved in our particular pathology and then block it. However, we now know that there are at least a dozen ways for neurons to die, that blocking a particular mechanism of cell death may not prevent the cell from dying, and that non-neuronal cells also contribute to neuronal death. We review here the mechanisms of neuronal death by intrinsic and extrinsic apoptosis, oncosis, necroptosis, parthanatos, ferroptosis, sarmoptosis, autophagic cell death, autosis, autolysis, paraptosis, pyroptosis, phagoptosis, and mitochondrial permeability transition. We next explore the mechanisms of neuronal death during development, and those induced by axotomy, aberrant cell-cycle reentry, glutamate (excitoxicity and oxytosis), loss of connected neurons, aggregated proteins and the unfolded protein response, oxidants, inflammation, and microglia. We then reassess which forms of cell death occur in stroke and Alzheimer's disease, two of the most important pathologies involving neuronal cell death. We also discuss why it has been so difficult to pinpoint the type of neuronal death involved, if and why the mechanism of neuronal death matters, the molecular overlap and interplay between death subroutines, and the therapeutic implications of these multiple overlapping forms of neuronal death.
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Affiliation(s)
- Michael Fricker
- Hunter Medical Research Institute, University of Newcastle, Callaghan, New South Wales , Australia ; Department of Clinical Neurosciences, University of Cambridge , Cambridge , United Kingdom ; Neuroscience Institute, Lithuanian University of Health Sciences , Kaunas , Lithuania ; and Department of Biochemistry, University of Cambridge , Cambridge , United Kingdom
| | - Aviva M Tolkovsky
- Hunter Medical Research Institute, University of Newcastle, Callaghan, New South Wales , Australia ; Department of Clinical Neurosciences, University of Cambridge , Cambridge , United Kingdom ; Neuroscience Institute, Lithuanian University of Health Sciences , Kaunas , Lithuania ; and Department of Biochemistry, University of Cambridge , Cambridge , United Kingdom
| | - Vilmante Borutaite
- Hunter Medical Research Institute, University of Newcastle, Callaghan, New South Wales , Australia ; Department of Clinical Neurosciences, University of Cambridge , Cambridge , United Kingdom ; Neuroscience Institute, Lithuanian University of Health Sciences , Kaunas , Lithuania ; and Department of Biochemistry, University of Cambridge , Cambridge , United Kingdom
| | - Michael Coleman
- Hunter Medical Research Institute, University of Newcastle, Callaghan, New South Wales , Australia ; Department of Clinical Neurosciences, University of Cambridge , Cambridge , United Kingdom ; Neuroscience Institute, Lithuanian University of Health Sciences , Kaunas , Lithuania ; and Department of Biochemistry, University of Cambridge , Cambridge , United Kingdom
| | - Guy C Brown
- Hunter Medical Research Institute, University of Newcastle, Callaghan, New South Wales , Australia ; Department of Clinical Neurosciences, University of Cambridge , Cambridge , United Kingdom ; Neuroscience Institute, Lithuanian University of Health Sciences , Kaunas , Lithuania ; and Department of Biochemistry, University of Cambridge , Cambridge , United Kingdom
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33
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Kumar H, Lee SH, Kim KT, Zeng X, Han I. TRPV4: a Sensor for Homeostasis and Pathological Events in the CNS. Mol Neurobiol 2018; 55:8695-8708. [PMID: 29582401 DOI: 10.1007/s12035-018-0998-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Accepted: 03/07/2018] [Indexed: 01/22/2023]
Abstract
Transient receptor potential vanilloid type 4 (TRPV4) was originally described as a calcium-permeable nonselective cation channel. TRPV4 is now recognized as a polymodal ionotropic receptor: it is a broadly expressed, nonselective cation channel (permeable to calcium, potassium, magnesium, and sodium) that plays an important role in a multitude of physiological processes. TRPV4 is involved in maintaining homeostasis, serves as an osmosensor and thermosensor, can be activated directly by endogenous or exogenous chemical stimuli, and can be activated or sensitized indirectly via intracellular signaling pathways. Additionally, TRPV4 is upregulated in a variety of pathological conditions. In this review, we focus on the role of TRPV4 in mediating homeostasis and pathological events in the central nervous system (CNS). This review is composed of three parts. Section 1 describes the role of TRPV4 in maintaining homeostatic processes, including the volume of body water, ionic concentrations, volume, and the temperature. Section 2 describes the effects of activation and inhibition of TRPV4 in the CNS. Section 3 focuses on the role of TRPV4 during pathological events in CNS.
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Affiliation(s)
- Hemant Kumar
- Department of Neurosurgery, CHA University, CHA Bundang Medical Center, Seongnam-si, Gyeonggi-do, 13496, Republic of Korea
| | - Soo-Hong Lee
- Department of Biomedical Science, CHA University, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - Kyoung-Tae Kim
- Department of Neurosurgery, Kyungpook National University Hospital, 130, Dongdeok-ro, Jung-gu, Daegu, 41944, Republic of Korea
| | - Xiang Zeng
- Department of Histology and Embryology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, 510080, China.
| | - Inbo Han
- Department of Neurosurgery, CHA University, CHA Bundang Medical Center, Seongnam-si, Gyeonggi-do, 13496, Republic of Korea.
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34
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Rakela B, Brehm P, Mandel G. Astrocytic modulation of excitatory synaptic signaling in a mouse model of Rett syndrome. eLife 2018; 7:31629. [PMID: 29313799 PMCID: PMC5771668 DOI: 10.7554/elife.31629] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 01/08/2018] [Indexed: 12/16/2022] Open
Abstract
Studies linking mutations in Methyl CpG Binding Protein 2 (MeCP2) to physiological defects in the neurological disease, Rett syndrome, have focused largely upon neuronal dysfunction despite MeCP2 ubiquitous expression. Here we explore roles for astrocytes in neuronal network function using cortical slice recordings. We find that astrocyte stimulation in wild-type mice increases excitatory synaptic activity that is absent in male mice lacking MeCP2 globally. To determine the cellular basis of the defect, we exploit a female mouse model for Rett syndrome that expresses wild-type MeCP2-GFP in a mosaic distribution throughout the brain, allowing us to test all combinations of wild-type and mutant cells. We find that the defect is dependent upon MeCP2 expression status in the astrocytes and not in the neurons. Our findings highlight a new role for astrocytes in regulation of excitatory synaptic signaling and in the neurological defects associated with Rett syndrome.
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Affiliation(s)
- Benjamin Rakela
- Vollum Institute, Oregon Health & Science University, Portland, United States
| | - Paul Brehm
- Vollum Institute, Oregon Health & Science University, Portland, United States
| | - Gail Mandel
- Vollum Institute, Oregon Health & Science University, Portland, United States
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35
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Affiliation(s)
- Thaiz Rivera Vargas
- Centre de Recherche; INSERM U1231; Facultés de Médecine et de Pharmacie; Dijon France
- Faculté de Médecine; Université de Bourgogne Franche comté; Dijon France
| | - Lionel Apetoh
- Centre de Recherche; INSERM U1231; Facultés de Médecine et de Pharmacie; Dijon France
- Faculté de Médecine; Université de Bourgogne Franche comté; Dijon France
- Centre Georges François Leclerc; Dijon France
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36
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Datta I, Ganapathy K, Razdan R, Bhonde R. Location and Number of Astrocytes Determine Dopaminergic Neuron Survival and Function Under 6-OHDA Stress Mediated Through Differential BDNF Release. Mol Neurobiol 2017; 55:5505-5525. [PMID: 28965325 DOI: 10.1007/s12035-017-0767-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Accepted: 09/06/2017] [Indexed: 02/08/2023]
Abstract
While astrocytes throughout the CNS share many common traits, they exhibit significant differences in function and number among brain regions. The aim of the present study is to assess the effect of region-specificity and number of astrocytes on the survival of dopaminergic neurons under stress, and to understand the possible mechanism by which these astrocytes extend neuroprotection to dopaminergic neurons. Purified astrocytes obtained from forebrain, midbrain, and hindbrain region were characterized through FACS and immunofluorescence. Co-culture experiments (using trans-wells) were then performed to measure the effect of region-specificities and numbers of astrocytes on primary midbrain culture under 6-OHDA stress. Cell survival augmented with an increase in astrocyte seeding number and total cell survival was comparable among the different region-specific astrocytes for all numbers. However, striking differences were observed in dopaminergic neuronal (TH) cell survival in the presence of midbrain astrocytes in comparison to forebrain and hindbrain astrocytes at all seeding numbers. At 75 μM 6-OHDA insult, while cell survival was comparable in purified astrocytes from the different brain regions, a distinct increase in BDNF secretion (significantly higher than its constitutive release) was noted for midbrain astrocytes compared to forebrain and hindbrain astrocytes. The TH immunopositive population decreased when TrkB inhibitor was added to the co-culture under 6-OHDA toxicity, suggesting that BDNF released by co-cultured astrocytes plays a key role in the survival of dopaminergic neurons. This BDNF release decreased in presence of NO inhibitor and increased in the presence of NO donor (DETA/NO). We conclude that the BDNF released from astrocytes under 6-OHDA toxicity is mediated through NO release through both autocrine and paracrine signaling, and this BDNF release is primarily responsible for the differential effect of region-specific astrocytes on TH neuron survival under these conditions.
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Affiliation(s)
- Indrani Datta
- Department of Biophysics, National Institute of Mental Health and Neurosciences, an Institute of National Importance, P.B. No 2900, Hosur Road, Bengaluru, Karnataka, 560029, India.
| | - Kavina Ganapathy
- Department of Pharmacology, Al-Ameen College of Pharmacy, Bengaluru, Karnataka, India
| | - Rema Razdan
- School of Regenerative Medicine, Manipal University, Bengaluru, Karnataka, India
| | - Ramesh Bhonde
- Department of Pharmacology, Al-Ameen College of Pharmacy, Bengaluru, Karnataka, India
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Abstract
There is an increasing recognition that inflammation plays a critical role in neurodegenerative diseases of the CNS, including Alzheimer's disease, amyotrophic lateral sclerosis, Parkinson's disease, and the prototypic neuroinflammatory disease multiple sclerosis (MS). Differential immune responses involving the adaptive versus the innate immune system are observed at various stages of neurodegenerative diseases, and may not only drive disease processes but could serve as therapeutic targets. Ongoing investigations into the specific inflammatory mechanisms that play roles in disease causation and progression have revealed lessons about inflammation-driven neurodegeneration that can be applied to other neurodegenerative diseases. An increasing number of immunotherapeutic strategies that have been successful in MS are now being applied to other neurodegenerative diseases. Some approaches suppress CNS immune mechanisms, while others harness the immune system to clear deleterious products and cells. This Review focuses on the mechanisms by which inflammation, mediated either by the peripheral immune response or by endogenous CNS immune mechanisms, can affect CNS neurodegeneration.
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Steady-State Free Ca 2+ in Astrocytes Is Decreased by Experience and Impacts Arteriole Tone. J Neurosci 2017; 37:8150-8165. [PMID: 28733356 DOI: 10.1523/jneurosci.0239-17.2017] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 06/23/2017] [Accepted: 07/10/2017] [Indexed: 12/27/2022] Open
Abstract
Astrocytes can control basal synaptic strength and arteriole tone via their resting Ca2+ activity. However, whether resting astrocyte Ca2+ can adjust to a new steady-state level, with an impact on surrounding brain cells, remains unknown. Using two-photon Ca2+ imaging in male rat acute brain slices of the somatosensory neocortex, we found that theta burst neural activity produced an unexpected long-lasting reduction in astrocyte free Ca2+ in the soma and endfeet. The drop in intracellular Ca2+ was attenuated by antagonists targeting multiple ionotropic and metabotropic glutamate receptors, and intracellular cascades involved Ca2+ stores and nitric oxide. The reduction in astrocyte endfoot Ca2+ was coincident with an increase in arteriole tone, and both the Ca2+ drop and the tone change were prevented by an NMDA receptor antagonist. Astrocyte patch-clamp experiments verified that the glutamate receptors in question were located on astrocytes and that Ca2+ changes within astrocytes were responsible for the long-lasting change in arteriole diameter caused by theta burst neural activity. In astrocytes from animals that lived in an enriched environment, we measured a relatively lower resting Ca2+ level that occluded any further drop in Ca2+ in response to theta burst activity. These data suggest that electrically evoked patterns of neural activity or natural experience can adjust steady-state resting astrocyte Ca2+ and that the effect has an impact on basal arteriole diameter.SIGNIFICANCE STATEMENT The field of astrocyte-neuron and astrocyte-arteriole interactions is currently in a state of refinement. Experimental evidence ex vivo suggests that direct manipulation of astrocyte-free Ca2+ regulates synaptic signaling and local blood flow control; however, in vivo experiments fail to link synaptically evoked astrocyte Ca2+ transients and immediate changes to various astrocyte-mediated processes. To clarify this discrepancy, we examined a different aspect of astrocyte Ca2+: the resting, steady-state free Ca2+ of astrocytes, its modulation, and its potential role in the tonic regulation of surrounding brain cells. We found that ex vivo or in vivo neural activity induced a long-lasting reduction in resting free astrocyte Ca2+ and that this phenomenon changed arteriole tone.
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Vlachaki Walker JM, Robb JL, Cruz AM, Malhi A, Weightman Potter PG, Ashford MLJ, McCrimmon RJ, Ellacott KLJ, Beall C. AMP-activated protein kinase (AMPK) activator A-769662 increases intracellular calcium and ATP release from astrocytes in an AMPK-independent manner. Diabetes Obes Metab 2017; 19:997-1005. [PMID: 28211632 DOI: 10.1111/dom.12912] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 02/09/2017] [Accepted: 02/14/2017] [Indexed: 12/18/2022]
Abstract
AIM To test the hypothesis that, given the role of AMP-activated protein kinase (AMPK) in regulating intracellular ATP levels, AMPK may alter ATP release from astrocytes, the main sources of extracellular ATP (eATP) within the brain. MATERIALS AND METHODS Measurements of ATP release were made from human U373 astrocytoma cells, primary mouse hypothalamic (HTAS) and cortical astrocytes (CRTAS) and wild-type and AMPK α1/α2 null mouse embryonic fibroblasts (MEFs). Cells were treated with drugs known to modulate AMPK activity: A-769662, AICAR and metformin, for up to 3 hours. Intracellular calcium was measured using Fluo4 and Fura-2 calcium-sensitive fluorescent dyes. RESULTS In U373 cells, A-769662 (100 μM) increased AMPK phosphorylation, whereas AICAR and metformin (1 mM) induced a modest increase or had no effect, respectively. Only A-769662 increased eATP levels, and this was partially blocked by AMPK inhibitor Compound C. A-769662-induced increases in eATP were preserved in AMPK α1/α2 null MEF cells. A-769662 increased intracellular calcium in U373, HTAS and CRTAS cells and chelation of intracellular calcium using BAPTA-AM reduced A-769662-induced eATP levels. A-769662 also increased ATP release from a number of other central and peripheral endocrine cell types. CONCLUSIONS AMPK is required to maintain basal eATP levels but is not required for A-769662-induced increases in eATP. A-769662 (>50 μM) enhanced intracellular calcium levels leading to ATP release in an AMPK and purinergic receptor independent pathway.
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Affiliation(s)
- Julia M Vlachaki Walker
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Exeter, UK
- Division of Molecular and Clinical Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - Josephine L Robb
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Exeter, UK
| | - Ana M Cruz
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Exeter, UK
| | - Amrinder Malhi
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Exeter, UK
| | - Paul G Weightman Potter
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Exeter, UK
| | - Michael L J Ashford
- Division of Molecular and Clinical Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - Rory J McCrimmon
- Division of Molecular and Clinical Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - Kate L J Ellacott
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Exeter, UK
| | - Craig Beall
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Exeter, UK
- Division of Molecular and Clinical Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
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Astrocytic Pathological Calcium Homeostasis and Impaired Vesicle Trafficking in Neurodegeneration. Int J Mol Sci 2017; 18:ijms18020358. [PMID: 28208745 PMCID: PMC5343893 DOI: 10.3390/ijms18020358] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Revised: 01/30/2017] [Accepted: 01/31/2017] [Indexed: 02/08/2023] Open
Abstract
Although the central nervous system (CNS) consists of highly heterogeneous populations of neurones and glial cells, clustered into diverse anatomical regions with specific functions, there are some conditions, including alertness, awareness and attention that require simultaneous, coordinated and spatially homogeneous activity within a large area of the brain. During such events, the brain, representing only about two percent of body mass, but consuming one fifth of body glucose at rest, needs additional energy to be produced. How simultaneous energy procurement in a relatively extended area of the brain takes place is poorly understood. This mechanism is likely to be impaired in neurodegeneration, for example in Alzheimer’s disease, the hallmark of which is brain hypometabolism. Astrocytes, the main neural cell type producing and storing glycogen, a form of energy in the brain, also hold the key to metabolic and homeostatic support in the central nervous system and are impaired in neurodegeneration, contributing to the slow decline of excitation-energy coupling in the brain. Many mechanisms are affected, including cell-to-cell signalling. An important question is how changes in cellular signalling, a process taking place in a rather short time domain, contribute to the neurodegeneration that develops over decades. In this review we focus initially on the slow dynamics of Alzheimer’s disease, and on the activity of locus coeruleus, a brainstem nucleus involved in arousal. Subsequently, we overview much faster processes of vesicle traffic and cytosolic calcium dynamics, both of which shape the signalling landscape of astrocyte-neurone communication in health and neurodegeneration.
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Portillo JAC, Lopez Corcino Y, Miao Y, Tang J, Sheibani N, Kern TS, Dubyak GR, Subauste CS. CD40 in Retinal Müller Cells Induces P2X7-Dependent Cytokine Expression in Macrophages/Microglia in Diabetic Mice and Development of Early Experimental Diabetic Retinopathy. Diabetes 2017; 66:483-493. [PMID: 27474370 PMCID: PMC5248988 DOI: 10.2337/db16-0051] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 07/07/2016] [Indexed: 12/11/2022]
Abstract
Müller cells and macrophages/microglia are likely important for the development of diabetic retinopathy; however, the interplay between these cells in this disease is not well understood. An inflammatory process is linked to the onset of experimental diabetic retinopathy. CD40 deficiency impairs this process and prevents diabetic retinopathy. Using mice with CD40 expression restricted to Müller cells, we identified a mechanism by which Müller cells trigger proinflammatory cytokine expression in myeloid cells. During diabetes, mice with CD40 expressed in Müller cells upregulated retinal tumor necrosis factor-α (TNF-α), interleukin 1β (IL-1β), intracellular adhesion molecule 1 (ICAM-1), and nitric oxide synthase (NOS2), developed leukostasis and capillary degeneration. However, CD40 did not cause TNF-α or IL-1β secretion in Müller cells. TNF-α was not detected in Müller cells from diabetic mice with CD40+ Müller cells. Rather, TNF-α was upregulated in macrophages/microglia. CD40 ligation in Müller cells triggered phospholipase C-dependent ATP release that caused P2X7-dependent production of TNF-α and IL-1β by macrophages. P2X7-/- mice and mice treated with a P2X7 inhibitor were protected from diabetes-induced TNF-α, IL-1β, ICAM-1, and NOS2 upregulation. Our studies indicate that CD40 in Müller cells is sufficient to upregulate retinal inflammatory markers and appears to promote experimental diabetic retinopathy and that Müller cells orchestrate inflammatory responses in myeloid cells through a CD40-ATP-P2X7 pathway.
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Affiliation(s)
- Jose-Andres C Portillo
- Division of Infectious Diseases and HIV Medicine, Department of Medicine, Case Western Reserve University, Cleveland, OH
| | - Yalitza Lopez Corcino
- Division of Infectious Diseases and HIV Medicine, Department of Medicine, Case Western Reserve University, Cleveland, OH
| | - Yanling Miao
- Division of Infectious Diseases and HIV Medicine, Department of Medicine, Case Western Reserve University, Cleveland, OH
| | - Jie Tang
- Division of Molecular Endocrinology, Department of Medicine, Case Western Reserve University, Cleveland, OH
| | - Nader Sheibani
- Department of Ophthalmology, University of Wisconsin-Madison, Madison, WI
| | - Timothy S Kern
- Division of Molecular Endocrinology, Department of Medicine, Case Western Reserve University, Cleveland, OH
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH
- Louis Stokes Cleveland Veterans Administration Medical Center, Research Service 151, Cleveland, OH
| | - George R Dubyak
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH
| | - Carlos S Subauste
- Division of Infectious Diseases and HIV Medicine, Department of Medicine, Case Western Reserve University, Cleveland, OH
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH
- Department of Pathology, Case Western Reserve University, Cleveland, OH
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42
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O'Hare Doig RL, Bartlett CA, Smith NM, Hodgetts SI, Dunlop SA, Hool L, Fitzgerald M. Specific combinations of ion channel inhibitors reduce excessive Ca 2+ influx as a consequence of oxidative stress and increase neuronal and glial cell viability in vitro. Neuroscience 2016; 339:450-462. [PMID: 27725216 DOI: 10.1016/j.neuroscience.2016.10.005] [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: 06/08/2016] [Revised: 09/15/2016] [Accepted: 10/02/2016] [Indexed: 01/02/2023]
Abstract
Combinations of Ca2+ channel inhibitors have been proposed as an effective means to prevent excess Ca2+ flux and death of neurons and glia following neurotrauma in vivo. However, it is not yet known if beneficial outcomes such as improved viability have been due to direct effects on intracellular Ca2+ concentrations. Here, the effects of combinations of Lomerizine (Lom), 2,3-dioxo-7-(1H-imidazol-1-yl)6-nitro-1,2,3,4-tetrahydro-1-quinoxalinyl]acetic acid monohydrate (YM872), 3,5-dimethyl-1-adamantanamine (memantine (Mem)) and/or adenosine 5'-triphosphate periodate oxidized sodium salt (oxATP) to block voltage-gated Ca2+ channels, Ca2+ permeable α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, NMDA receptors and purinergic P2X7 receptors (P2X7R) respectively, on Ca2+ concentration and viability of rat primary mixed cortical (MC) cultures exposed to hydrogen peroxide (H2O2) insult, were assessed. The contribution of ryanodine-sensitive intracellular stores to intracellular Ca2+ concentration was also assessed. Live cell calcium imaging revealed that a 30min H2O2 insult induced a slow increase in intracellular Ca2+, in part from intracellular sources, associated with loss of cell viability by 6h. Most combinations of inhibitors that included oxATP significantly decreased Ca2+ influx and increased cell viability when administered simultaneously with H2O2. However, reductions in intracellular Ca2+ concentration were not always linked to improved cell viability. Examination of the density of specific cell subpopulations demonstrated that most combinations of inhibitors that included oxATP preserved NG2+ non-oligodendroglial cells, but preservation of astrocytes and neurons required additional inhibitors. Olig2+ oligodendroglia and ED-1+ activated microglia/macrophages were not preserved by any of the inhibitor combinations. These data indicate that following H2O2 insult, limiting intracellular Ca2+ entry via P2X7R is generally associated with increased cell viability. Protection of NG2+ non-oligodendroglial cells by Ca2+ channel inhibitor combinations may contribute to observed beneficial outcomes in vivo.
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Affiliation(s)
- Ryan L O'Hare Doig
- Experimental and Regenerative Neurosciences, The University of Western Australia, Crawley, Western Australia, Australia; School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia; School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Carole A Bartlett
- Experimental and Regenerative Neurosciences, The University of Western Australia, Crawley, Western Australia, Australia; School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Nicole M Smith
- Experimental and Regenerative Neurosciences, The University of Western Australia, Crawley, Western Australia, Australia; School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia; School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, Australia
| | - Stuart I Hodgetts
- Experimental and Regenerative Neurosciences, The University of Western Australia, Crawley, Western Australia, Australia; School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Sarah A Dunlop
- Experimental and Regenerative Neurosciences, The University of Western Australia, Crawley, Western Australia, Australia; School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Livia Hool
- School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, Western Australia, Australia; Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
| | - Melinda Fitzgerald
- Experimental and Regenerative Neurosciences, The University of Western Australia, Crawley, Western Australia, Australia; School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia.
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Involvement of P2X 7 receptors in retinal ganglion cell apoptosis induced by activated Müller cells. Exp Eye Res 2016; 153:42-50. [PMID: 27720859 DOI: 10.1016/j.exer.2016.10.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 08/25/2016] [Accepted: 10/05/2016] [Indexed: 12/22/2022]
Abstract
Müller cell reactivation (gliosis) is an early response in glaucomatous retina. Previous studies have demonstrated that activation of P2X7 receptors results in retinal ganglion cell (RGC) apoptosis. Here, the issues of whether and how activated Müller cells may contribute to RGC apoptosis through P2X7 receptors were investigated. Either intravitreal injection of (S)-3,5-dihydroxyphenylglycine (DHPG), a group I metabotropic glutamate receptor (mGluR I) agonist, in normal rat retinas, or DHPG treatment of purified cultured rat retinal Müller cells induced an increase in glial fibrillary acidic protein (GFAP) expression, indicative of Müller cell gliosis. In addition, an increase in adenosine triphosphate (ATP) release from purified cultured Müller cells was detected during DHPG treatment (for 10 min to 48 h), which was mediated by the intracellular mGluR5/Gq/PI-PLC/PKC signaling pathway. Intravitreal injection of DHPG mimicked the reduction in the number of fluorogold retrogradely labeled RGCs in chronic ocular hypertension (COH) rats. Treatment with the conditioned culture medium (CM) obtained from the DHPG-activated Müller cell medium induced an increase in the number of TUNEL-positive cells in cultured RGCs, which was mimicked by benzoylbenzoyl adenosine triphosphate (BzATP), a P2X7 receptor agonist, but was partially blocked by brilliant blue G (BBG), a P2X7 receptor antagonist. Moreover, the CM treatment of cultured RGCs significantly increased Bax protein level and decreased Bcl-2 protein level, which was also mimicked by BzATP and partially blocked by BBG, respectively. These results suggest that reactivated Müller cells may release excessive ATP, in turn leading to RGC apoptosis through activating P2X7 receptors in these cells.
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44
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Sweeney P, Qi Y, Xu Z, Yang Y. Activation of hypothalamic astrocytes suppresses feeding without altering emotional states. Glia 2016; 64:2263-2273. [PMID: 27658520 DOI: 10.1002/glia.23073] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 08/01/2016] [Accepted: 09/08/2016] [Indexed: 02/06/2023]
Abstract
Emerging evidence shows that hypothalamic astrocytes react to and counteract energy surfeit produced by high-fat diet (HFD) feeding. However, the functional role of astrocytes in the control of energy states and the underlying molecular mechanism(s) during physiological conditions remain largely underexplored. In the present study, by taking advantage of spatiotemporally precise optogenetic approaches, real-time measurements of extracellular adenosine, and behavioral assays, we find that optogenetic stimulation of astrocytes localized in the medial basal hypothalamus (MBH) suppresses food intake in a frequency dependent manner with high frequency, but not low frequency, stimulation of astrocytes reducing food intake. Furthermore, stimulation of MBH astrocytes diminishes orexigenic ghrelin or fasting-induced hyperphagia without effecting anxiety-related behavior. Consistent with a frequency dependent role for MBH astrocytes in feeding behavior, optogenetic stimulation of MBH astrocytes increases extracellular levels of adenosine in a frequency dependent manner. Collectively, our results provide new insights into the role of astrocytes in physiological functions during naturally occurring behaviors, such as feeding. GLIA 2016;64:2263-2273.
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Affiliation(s)
- Patrick Sweeney
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York
| | - Yong Qi
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York.,Zhengzhou University People's Hospital (He'nan Provincial People's Hospital), Zhengzhou, 450003, China
| | - Zhenping Xu
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York
| | - Yunlei Yang
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York.
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45
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Activated Müller Cells Involved in ATP-Induced Upregulation of P2X 7 Receptor Expression and Retinal Ganglion Cell Death. BIOMED RESEARCH INTERNATIONAL 2016; 2016:9020715. [PMID: 27738636 PMCID: PMC5050355 DOI: 10.1155/2016/9020715] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 08/10/2016] [Accepted: 08/28/2016] [Indexed: 11/17/2022]
Abstract
P2X7 receptor (P2X7R), an ATP-gated ion channel, plays an important role in glaucomatous retinal ganglion cell (RGC) apoptotic death, in which activated retinal Müller glial cells may be involved by releasing ATP. In the present study, we investigated whether and how activated Müller cells may induce changes in P2X7R expression in RGCs by using immunohistochemistry and Western blot techniques. Intravitreal injection of DHPG, a group I metabotropic glutamate receptor (mGluR I) agonist, induced upregulation of GFAP expression, suggestive of Müller cell activation (gliosis), as we previously reported. Accompanying Müller cell activation, P2X7R protein expression was upregulated, especially in the cells of ganglion cell layer (GCL), which was reversed by coinjection of brilliant blue G (BBG), a P2X7R blocker. In addition, intravitreal injection of ATP also induced upregulation of P2X7R protein expression. Similar results were observed in cultured retinal neurons by ATP treatment. Moreover, both DHPG and ATP intravitreal injection induced a reduction in the number of fluorogold retrogradely labeled RGCs, and the DHPG effect was partially rescued by coinjection of BBG. All these results suggest that activated Müller cells may release ATP and, in turn, induce upregulation of P2X7R expression in the cells of GCL, thus contributing to RGC death.
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46
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Zorec R, Parpura V, Verkhratsky A. Astroglial Vesicular Trafficking in Neurodegenerative Diseases. Neurochem Res 2016; 42:905-917. [DOI: 10.1007/s11064-016-2055-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 08/30/2016] [Accepted: 08/31/2016] [Indexed: 12/20/2022]
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47
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Rezq S, Abdel-Rahman AA. Rostral Ventrolateral Medulla EP3 Receptor Mediates the Sympathoexcitatory and Pressor Effects of Prostaglandin E2 in Conscious Rats. J Pharmacol Exp Ther 2016; 359:290-299. [PMID: 27572469 DOI: 10.1124/jpet.116.233502] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 08/25/2016] [Indexed: 12/13/2022] Open
Abstract
Whereas few studies have dealt with the central sympathoexcitatory action of the inflammatory prostanoid prostaglandin E2 (PGE2), there is no information on the expression and cardiovascular function of different PGE2 (EP) receptors in one of the major cardiovascular-regulating nuclei, the rostral ventrolateral medulla (RVLM). The current study aimed at filling this knowledge gap as well as elucidating the implicated molecular mechanisms. To achieve these goals, we showed the expression of EP2, EP3, and EP4 receptors in the RVLM and investigated their cardiovascular roles in conscious rats, ex vivo as well as in cultured PC12 cells. Intra-RVLM PGE2 significantly increased blood pressure and sympathetic dominance (spectral analysis). Studies with selective EP receptor subtype agonists and antagonists showed that these PGE2-evoked responses were only replicated by intra-RVLM activation of the EP3 receptor with its agonist sulprostone. The RVLM of PGE2-treated rats exhibited increases in c-Fos expression and extracellular signal-regulated kinase 1/2 and neuronal nitric oxide synthase phosphorylation along with oxidative stress, and PGE2 increased l-glutamate release in PC12 cells (surrogates of RVLM neurons). Abrogation of the PGE2-evoked pressor and biochemical responses only occurred following EP3 receptor blockade (N-[(5-Bromo-2-methoxyphenyl)sulfonyl]-3-[2-(2-naphthalenylmethyl)phenyl]-2-propenamide, L-798106). These findings suggest the dependence of RVLM PGE2-mediated sympathoexcitation/pressor response on local EP3 receptor signaling in conscious rats, and highlight central EP3 receptor blockade as a potential therapeutic modality for hypertension management.
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Affiliation(s)
- Samar Rezq
- Department of Pharmacology, School of Medicine, East Carolina University, Greenville, North Carolina
| | - Abdel A Abdel-Rahman
- Department of Pharmacology, School of Medicine, East Carolina University, Greenville, North Carolina
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Purinergic P2Y1 Receptors Control Rapid Expression of Plasma Membrane Processes in Hippocampal Astrocytes. Mol Neurobiol 2016; 54:4081-4093. [PMID: 27318677 DOI: 10.1007/s12035-016-9955-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 06/06/2016] [Indexed: 10/21/2022]
Abstract
Astrocytes regulate neuronal activity and blood brain barrier through tiny plasma membrane branches or astrocytic processes (APs) making contact with synapses and brain vessels. Several transmitters released by astrocytes and exerting their action on several receptor classes expressed by astrocytes themselves influence their physiology. Here we found that APs are dynamically modulated by purines. In live imaging experiments carried out in rat hippocampal astrocytes, Gq-coupled P2Y1 receptor blockade with the selective antagonist MRS2179 (1 μM) or inhibition of its effector phospholipase C using U73122 (3 μM) produced APs retraction, while stimulation of the same receptor with the selective agonist 2MeSADP (100 μM) increased their number. Since astrocytes, among other transmitters, release ATP by several mechanisms including connexin hemichannels, we used the connexin hemichannel inhibitor carbenoxolone (100 μM) and APs retraction was observed. In our system we then measured expression or function of channels important for modulation of volume transmission and K+ buffering, aquaporin-4, and K+ inward rectifying (Kir) channels, respectively. Aquaporin-4 expression level did not change whereas, in whole-cell patch-clamp recordings performed to measure Kir current, we observed an increase in K+ current in all conditions where APs number was reduced. These data are supporting the idea of a dynamic modulation of astrocytic processes by purinergic signal, strengthening the role of purines in brain homeostasis.
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Switching from astrocytic neuroprotection to neurodegeneration by cytokine stimulation. Arch Toxicol 2016; 91:231-246. [PMID: 27052459 DOI: 10.1007/s00204-016-1702-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 03/21/2016] [Indexed: 12/12/2022]
Abstract
Astrocytes, the largest cell population in the human brain, are powerful inflammatory effectors. Several studies have examined the interaction of activated astrocytes with neurons, but little is known yet about human neurotoxicity under such situations and about strategies of neuronal rescue. To address this question, immortalized murine astrocytes (IMA) were combined with human LUHMES neurons and stimulated with an inflammatory (TNF, IL-1) cytokine mix (CM). Neurotoxicity was studied both in co-cultures and in monocultures after transfer of conditioned medium from activated IMA. Interventions with >20 drugs were used to profile the model system. Control IMA supported neurons and protected them from neurotoxicants. Inflammatory activation reduced this protection, and prolonged exposure of co-cultures to CM triggered neurotoxicity. Neither the added cytokines nor the release of NO from astrocytes were involved in this neurodegeneration. The neurotoxicity-mediating effect of IMA was faithfully reproduced by human astrocytes. Moreover, glia-dependent toxicity was also observed, when IMA cultures were stimulated with CM, and the culture medium was transferred to neurons. Such neurotoxicity was prevented when astrocytes were treated by p38 kinase inhibitors or dexamethasone, whereas such compounds had no effect when added to neurons. Conversely, treatment of neurons with five different drugs, including resveratrol and CEP1347, prevented toxicity of astrocyte supernatants. Thus, the sequential IMA-LUHMES neuroinflammation model is suitable for separate profiling of both glial-directed and directly neuroprotective strategies. Moreover, direct evaluation in co-cultures of the same cells allows for testing of therapeutic effectiveness in more complex settings, in which astrocytes affect pharmacological properties of neurons.
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P2Y Receptors in Synaptic Transmission and Plasticity: Therapeutic Potential in Cognitive Dysfunction. Neural Plast 2016; 2016:1207393. [PMID: 27069691 PMCID: PMC4812485 DOI: 10.1155/2016/1207393] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 02/10/2016] [Indexed: 01/02/2023] Open
Abstract
ATP released from neurons and astrocytes during neuronal activity or under pathophysiological circumstances is able to influence information flow in neuronal circuits by activation of ionotropic P2X and metabotropic P2Y receptors and subsequent modulation of cellular excitability, synaptic strength, and plasticity. In the present paper we review cellular and network effects of P2Y receptors in the brain. We show that P2Y receptors inhibit the release of neurotransmitters, modulate voltage- and ligand-gated ion channels, and differentially influence the induction of synaptic plasticity in the prefrontal cortex, hippocampus, and cerebellum. The findings discussed here may explain how P2Y1 receptor activation during brain injury, hypoxia, inflammation, schizophrenia, or Alzheimer's disease leads to an impairment of cognitive processes. Hence, it is suggested that the blockade of P2Y1 receptors may have therapeutic potential against cognitive disturbances in these states.
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