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Xu Y, Tang L, Zhou C, Sun L, Hu Y, Zhang Z, Xia S, Bao X, Yang H, Xu Y. Inhibition of ADORA3 promotes microglial phagocytosis and alleviates chronic ischemic white matter injury. CNS Neurosci Ther 2024; 30:e14742. [PMID: 38715283 PMCID: PMC11076989 DOI: 10.1111/cns.14742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 03/31/2024] [Accepted: 04/13/2024] [Indexed: 05/12/2024] Open
Abstract
BACKGROUND Adenosine A3 receptor (ADORA3) belongs to the adenosine receptor families and the role of ADORA3 in vascular dementia (VaD) is largely unexplored. The present study sought to determine the therapeutic role of ADORA3 antagonist in a mouse model of VaD. METHODS The GSE122063 dataset was selected to screen the differential expression genes and pathways between VaD patients and controls. A mouse model of bilateral carotid artery stenosis (BCAS) was established. The cognitive functions were examined by the novel object recognition test, Y maze test, and fear of conditioning test. The white matter injury (WMI) was examined by 9.4 T MRI, western blot, and immunofluorescence staining. The mechanisms of ADORA3-regulated phagocytosis by microglia were examined using qPCR, western blot, dual immunofluorescence staining, and flow cytometry. RESULTS The expression of ADORA3 was elevated in brain tissues of VaD patients and ADORA3 was indicated as a key gene for VaD in the GSE122063. In BCAS mice, the expression of ADORA3 was predominantly elevated in microglia in the corpus callosum. ADORA3 antagonist promotes microglial phagocytosis to myelin debris by facilitating cAMP/PKA/p-CREB pathway and thereby ameliorates WMI and cognitive impairment in BCAS mice. The therapeutic effect of ADORA3 antagonist was partially reversed by the inhibition of the cAMP/PKA pathway. CONCLUSIONS ADORA3 antagonist alleviates chronic ischemic WMI by modulating myelin clearance of microglia, which may be a potential therapeutic target for the treatment of VaD.
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Affiliation(s)
- Yuhao Xu
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical SchoolNanjing UniversityNanjingChina
- State Key Laboratory of Pharmaceutical Biotechnology and Institute of Translational Medicine for Brain Critical DiseasesNanjing UniversityNanjingChina
- Jiangsu Key Laboratory for Molecular MedicineMedical School of Nanjing UniversityNanjingChina
- Nanjing Neurology Clinical Medical CenterNanjingChina
| | - Limoran Tang
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical SchoolNanjing UniversityNanjingChina
- State Key Laboratory of Pharmaceutical Biotechnology and Institute of Translational Medicine for Brain Critical DiseasesNanjing UniversityNanjingChina
- Jiangsu Key Laboratory for Molecular MedicineMedical School of Nanjing UniversityNanjingChina
- Nanjing Neurology Clinical Medical CenterNanjingChina
| | - Chao Zhou
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical SchoolNanjing UniversityNanjingChina
- State Key Laboratory of Pharmaceutical Biotechnology and Institute of Translational Medicine for Brain Critical DiseasesNanjing UniversityNanjingChina
- Jiangsu Key Laboratory for Molecular MedicineMedical School of Nanjing UniversityNanjingChina
- Nanjing Neurology Clinical Medical CenterNanjingChina
| | - Liang Sun
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical SchoolNanjing UniversityNanjingChina
- State Key Laboratory of Pharmaceutical Biotechnology and Institute of Translational Medicine for Brain Critical DiseasesNanjing UniversityNanjingChina
- Jiangsu Key Laboratory for Molecular MedicineMedical School of Nanjing UniversityNanjingChina
- Nanjing Neurology Clinical Medical CenterNanjingChina
| | - Yujie Hu
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical SchoolNanjing UniversityNanjingChina
- State Key Laboratory of Pharmaceutical Biotechnology and Institute of Translational Medicine for Brain Critical DiseasesNanjing UniversityNanjingChina
- Jiangsu Key Laboratory for Molecular MedicineMedical School of Nanjing UniversityNanjingChina
- Nanjing Neurology Clinical Medical CenterNanjingChina
| | - Zhi Zhang
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical SchoolNanjing UniversityNanjingChina
- State Key Laboratory of Pharmaceutical Biotechnology and Institute of Translational Medicine for Brain Critical DiseasesNanjing UniversityNanjingChina
- Jiangsu Key Laboratory for Molecular MedicineMedical School of Nanjing UniversityNanjingChina
- Nanjing Neurology Clinical Medical CenterNanjingChina
| | - Shengnan Xia
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical SchoolNanjing UniversityNanjingChina
- State Key Laboratory of Pharmaceutical Biotechnology and Institute of Translational Medicine for Brain Critical DiseasesNanjing UniversityNanjingChina
- Jiangsu Key Laboratory for Molecular MedicineMedical School of Nanjing UniversityNanjingChina
- Nanjing Neurology Clinical Medical CenterNanjingChina
| | - Xinyu Bao
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical SchoolNanjing UniversityNanjingChina
- State Key Laboratory of Pharmaceutical Biotechnology and Institute of Translational Medicine for Brain Critical DiseasesNanjing UniversityNanjingChina
- Jiangsu Key Laboratory for Molecular MedicineMedical School of Nanjing UniversityNanjingChina
- Nanjing Neurology Clinical Medical CenterNanjingChina
| | - Haiyan Yang
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical SchoolNanjing UniversityNanjingChina
- State Key Laboratory of Pharmaceutical Biotechnology and Institute of Translational Medicine for Brain Critical DiseasesNanjing UniversityNanjingChina
- Jiangsu Key Laboratory for Molecular MedicineMedical School of Nanjing UniversityNanjingChina
- Nanjing Neurology Clinical Medical CenterNanjingChina
| | - Yun Xu
- Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical SchoolNanjing UniversityNanjingChina
- State Key Laboratory of Pharmaceutical Biotechnology and Institute of Translational Medicine for Brain Critical DiseasesNanjing UniversityNanjingChina
- Jiangsu Key Laboratory for Molecular MedicineMedical School of Nanjing UniversityNanjingChina
- Nanjing Neurology Clinical Medical CenterNanjingChina
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Launay A, Nebie O, Vijaya Shankara J, Lebouvier T, Buée L, Faivre E, Blum D. The role of adenosine A 2A receptors in Alzheimer's disease and tauopathies. Neuropharmacology 2023; 226:109379. [PMID: 36572177 DOI: 10.1016/j.neuropharm.2022.109379] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 12/12/2022] [Accepted: 12/13/2022] [Indexed: 12/24/2022]
Abstract
Adenosine signals through four distinct G protein-coupled receptors that are located at various synapses, cell types and brain areas. Through them, adenosine regulates neuromodulation, neuronal signaling, learning and cognition as well as the sleep-wake cycle, all strongly impacted in neurogenerative disorders, among which Alzheimer's Disease (AD). AD is a complex form of cognitive deficits characterized by two pathological hallmarks: extracellular deposits of aggregated β-amyloid peptides and intraneuronal fibrillar aggregates of hyper- and abnormally phosphorylated Tau proteins. Both lesions contribute to the early dysfunction and loss of synapses which are strongly associated to the development of cognitive decline in AD patients. The present review focuses on the pathophysiological impact of the A2ARs dysregulation observed in cognitive area from AD patients. We are reviewing not only evidence of the cellular changes in A2AR levels in pathological conditions but also describe what is currently known about their consequences in term of synaptic plasticity, neuro-glial miscommunication and memory abilities. We finally summarize the proof-of-concept studies that support A2AR as credible targets and the clinical interest to repurpose adenosine drugs for the treatment of AD and related disorders. This article is part of the Special Issue on "Purinergic Signaling: 50 years".
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Affiliation(s)
- Agathe Launay
- Univ. Lille, Inserm, CHU Lille, UMR-S1172 LilNCog - Lille Neuroscience & Cognition, F-59000, Lille, France; Alzheimer and Tauopathies, LabEx DISTALZ, France
| | - Ouada Nebie
- Univ. Lille, Inserm, CHU Lille, UMR-S1172 LilNCog - Lille Neuroscience & Cognition, F-59000, Lille, France; Alzheimer and Tauopathies, LabEx DISTALZ, France
| | - Jhenkruthi Vijaya Shankara
- Univ. Lille, Inserm, CHU Lille, UMR-S1172 LilNCog - Lille Neuroscience & Cognition, F-59000, Lille, France; Alzheimer and Tauopathies, LabEx DISTALZ, France
| | - Thibaud Lebouvier
- Univ. Lille, Inserm, CHU Lille, UMR-S1172 LilNCog - Lille Neuroscience & Cognition, F-59000, Lille, France; Alzheimer and Tauopathies, LabEx DISTALZ, France; CHU Lille, Memory Clinic, Lille, France
| | - Luc Buée
- Univ. Lille, Inserm, CHU Lille, UMR-S1172 LilNCog - Lille Neuroscience & Cognition, F-59000, Lille, France; Alzheimer and Tauopathies, LabEx DISTALZ, France
| | - Emilie Faivre
- Univ. Lille, Inserm, CHU Lille, UMR-S1172 LilNCog - Lille Neuroscience & Cognition, F-59000, Lille, France; Alzheimer and Tauopathies, LabEx DISTALZ, France
| | - David Blum
- Univ. Lille, Inserm, CHU Lille, UMR-S1172 LilNCog - Lille Neuroscience & Cognition, F-59000, Lille, France; Alzheimer and Tauopathies, LabEx DISTALZ, France.
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3
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Hanalioglu S, Taskiran-Sag A, Karatas H, Donmez-Demir B, Yilmaz-Ozcan S, Eren-Kocak E, Gursoy-Ozdemir Y, Dalkara T. Cortical spreading depression can be triggered by sensory stimulation in primed wild type mouse brain: a mechanistic insight to migraine aura generation. J Headache Pain 2022; 23:107. [PMID: 35986251 PMCID: PMC9392331 DOI: 10.1186/s10194-022-01474-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 08/09/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Unlike the spontaneously appearing aura in migraineurs, experimentally, cortical spreading depression (CSD), the neurophysiological correlate of aura is induced by non-physiological stimuli. Consequently, neural mechanisms involved in spontaneous CSD generation, which may provide insight into how migraine starts in an otherwise healthy brain, remain largely unclear. We hypothesized that CSD can be physiologically induced by sensory stimulation in primed mouse brain.
Methods
Cortex was made susceptible to CSD with partial inhibition of Na+/K+-ATPase by epidural application of a low concentration of Na+/K+-ATPase blocker ouabain, allowing longer than 30-min intervals between CSDs or by knocking-down α2 subunit of Na+/K+-ATPase, which is crucial for K+ and glutamate re-uptake, with shRNA. Stimulation-triggered CSDs and extracellular K+ changes were monitored in vivo electrophysiologically and a K+-sensitive fluoroprobe (IPG-4), respectively.
Results
After priming with ouabain, photic stimulation significantly increased the CSD incidence compared with non-stimulated animals (44.0 vs. 4.9%, p < 0.001). Whisker stimulation also significantly increased the CSD incidence, albeit less effectively (14.9 vs. 2.4%, p = 0.02). Knocking-down Na+/K+-ATPase (50% decrease in mRNA) lowered the CSD threshold in all mice tested with KCl but triggered CSDs in 14.3% and 16.7% of mice with photic and whisker stimulation, respectively. Confirming Na+/K+-ATPase hypofunction, extracellular K+ significantly rose during sensory stimulation after ouabain or shRNA treatment unlike controls. In line with the higher CSD susceptibility observed, K+ rise was more prominent after ouabain. To gain insight to preventive mechanisms reducing the probability of stimulus-evoked CSDs, we applied an A1-receptor antagonist (DPCPX) to the occipital cortex, because adenosine formed during stimulation from ATP can reduce CSD susceptibility. DPCPX induced spontaneous CSDs but only small-DC shifts along with suppression of EEG spikes during photic stimulation, suggesting that the inhibition co-activated with sensory stimulation could limit CSD ignition when K+ uptake was not sufficiently suppressed as with ouabain.
Conclusions
Normal brain is well protected against CSD generation. For CSD to be ignited under physiological conditions, priming and predisposing factors are required as seen in migraine patients. Intense sensory stimulation has potential to trigger CSD when co-existing conditions bring extracellular K+ and glutamate concentrations over CSD-ignition threshold and stimulation-evoked inhibitory mechanisms are overcome.
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4
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Val C, Rodríguez-García C, Prieto-Díaz R, Crespo A, Azuaje J, Carbajales C, Majellaro M, Díaz-Holguín A, Brea JM, Loza MI, Gioé-Gallo C, Contino M, Stefanachi A, García-Mera X, Estévez JC, Gutiérrez-de-Terán H, Sotelo E. Optimization of 2-Amino-4,6-diarylpyrimidine-5-carbonitriles as Potent and Selective A 1 Antagonists. J Med Chem 2022; 65:2091-2106. [PMID: 35068155 PMCID: PMC8842224 DOI: 10.1021/acs.jmedchem.1c01636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Indexed: 11/29/2022]
Abstract
We herein document a large collection of 108 2-amino-4,6-disubstituted-pyrimidine derivatives as potent, structurally simple, and highly selective A1AR ligands. The most attractive ligands were confirmed as antagonists of the canonical cyclic adenosine monophosphate pathway, and some pharmacokinetic parameters were preliminarilly evaluated. The library, built through a reliable and efficient three-component reaction, comprehensively explored the chemical space allowing the identification of the most prominent features of the structure-activity and structure-selectivity relationships around this scaffold. These included the influence on the selectivity profile of the aromatic residues at positions R4 and R6 of the pyrimidine core but most importantly the prominent role to the unprecedented A1AR selectivity profile exerted by the methyl group introduced at the exocyclic amino group. The structure-activity relationship trends on both A1 and A2AARs were conveniently interpreted with rigorous free energy perturbation simulations, which started from the receptor-driven docking model that guided the design of these series.
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Affiliation(s)
- Cristina Val
- Centro
Singular de Investigación en Química Biolóxica
e Materiais Moleculares (CiQUS), Universidade
de Santiago de Compostela, Santiago de Compostela 15782, Spain
- Departamento
de Química Orgánica, Universidade
de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - Carlos Rodríguez-García
- Centro
Singular de Investigación en Química Biolóxica
e Materiais Moleculares (CiQUS), Universidade
de Santiago de Compostela, Santiago de Compostela 15782, Spain
- Departamento
de Química Orgánica, Universidade
de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - Rubén Prieto-Díaz
- Centro
Singular de Investigación en Química Biolóxica
e Materiais Moleculares (CiQUS), Universidade
de Santiago de Compostela, Santiago de Compostela 15782, Spain
- Departamento
de Química Orgánica, Universidade
de Santiago de Compostela, Santiago de Compostela 15782, Spain
- Department
of Cell and Molecular Biology, Uppsala University, Uppsala 75124, Sweden
| | - Abel Crespo
- Centro
Singular de Investigación en Química Biolóxica
e Materiais Moleculares (CiQUS), Universidade
de Santiago de Compostela, Santiago de Compostela 15782, Spain
- Departamento
de Química Orgánica, Universidade
de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - Jhonny Azuaje
- Centro
Singular de Investigación en Química Biolóxica
e Materiais Moleculares (CiQUS), Universidade
de Santiago de Compostela, Santiago de Compostela 15782, Spain
- Departamento
de Química Orgánica, Universidade
de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - Carlos Carbajales
- Centro
Singular de Investigación en Química Biolóxica
e Materiais Moleculares (CiQUS), Universidade
de Santiago de Compostela, Santiago de Compostela 15782, Spain
- Departamento
de Química Orgánica, Universidade
de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - Maria Majellaro
- Centro
Singular de Investigación en Química Biolóxica
e Materiais Moleculares (CiQUS), Universidade
de Santiago de Compostela, Santiago de Compostela 15782, Spain
- Departamento
de Química Orgánica, Universidade
de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | | | - José M. Brea
- Centro
Singular de Investigación en Medicina Molecular y Enfermedades
Crónicas (CiMUS), Universidade de
Santiago de Compostela, Santiago
de Compostela 15782, Spain
| | - Maria Isabel Loza
- Centro
Singular de Investigación en Medicina Molecular y Enfermedades
Crónicas (CiMUS), Universidade de
Santiago de Compostela, Santiago
de Compostela 15782, Spain
| | - Claudia Gioé-Gallo
- Centro
Singular de Investigación en Química Biolóxica
e Materiais Moleculares (CiQUS), Universidade
de Santiago de Compostela, Santiago de Compostela 15782, Spain
- Departamento
de Química Orgánica, Universidade
de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - Marialessandra Contino
- Dipartimento
di Farmacia-Scienze del Farmaco, Università
degli Studi di Bari ALDO MORO, via Orabona 4, Bari 70125, Italy
| | - Angela Stefanachi
- Dipartimento
di Farmacia-Scienze del Farmaco, Università
degli Studi di Bari ALDO MORO, via Orabona 4, Bari 70125, Italy
| | - Xerardo García-Mera
- Departamento
de Química Orgánica, Universidade
de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - Juan C. Estévez
- Centro
Singular de Investigación en Química Biolóxica
e Materiais Moleculares (CiQUS), Universidade
de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | | | - Eddy Sotelo
- Centro
Singular de Investigación en Química Biolóxica
e Materiais Moleculares (CiQUS), Universidade
de Santiago de Compostela, Santiago de Compostela 15782, Spain
- Departamento
de Química Orgánica, Universidade
de Santiago de Compostela, Santiago de Compostela 15782, Spain
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Pharmacological characterization of DPTN and other selective A 3 adenosine receptor antagonists. Purinergic Signal 2021; 17:737-746. [PMID: 34713378 DOI: 10.1007/s11302-021-09823-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 10/19/2021] [Indexed: 10/20/2022] Open
Abstract
The A3 adenosine receptor (AR) is emerging as an attractive drug target. Antagonists are proposed for the potential treatment of glaucoma and asthma. However, currently available A3AR antagonists are potent in human and some large animals, but weak or inactive in mouse and rat. In this study, we re-synthesized a previously reported A3AR antagonist, DPTN, and evaluated its affinity and selectivity at human, mouse, and rat ARs. We showed that DPTN, indeed, is a potent A3AR antagonist for all three species tested, albeit a little less selective for mouse and rat A3AR in comparison to the human A3AR. DPTN's Ki values at respective A1, A2A, A2B, and A3 receptors were (nM) 162, 121, 230, and 1.65 (human); 411, 830, 189, and 9.61 (mouse); and 333, 1147, 163, and 8.53 (rat). Its antagonist activity at both human and mouse A3ARs was confirmed in a cyclic AMP functional assay. Considering controversial use of currently commercially available A3AR antagonists in rats and mice, we also re-examined other commonly used and selective A3AR antagonists under the same experimental conditions. The Ki values of MRS1523 were shown to be 43.9, 349, and 216 nM at human, mouse, and rat A3ARs, respectively. MRS1191 and MRS1334 showed incomplete inhibition of [125I]I-AB-MECA binding to mouse and rat A3ARs, while potent human A3AR antagonists, MRS1220, MRE3008F20, PSB10, PSB-11, and VUF5574 were largely inactive. Thus, we demonstrated that DPTN and MRS1523 are among the only validated A3AR antagonists that can be possibly used (at an appropriate concentration) in mouse or rat to confirm an A3AR-related mechanism or function.
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Emerging roles of dysregulated adenosine homeostasis in brain disorders with a specific focus on neurodegenerative diseases. J Biomed Sci 2021; 28:70. [PMID: 34635103 PMCID: PMC8507231 DOI: 10.1186/s12929-021-00766-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 10/04/2021] [Indexed: 02/07/2023] Open
Abstract
In modern societies, with an increase in the older population, age-related neurodegenerative diseases have progressively become greater socioeconomic burdens. To date, despite the tremendous effort devoted to understanding neurodegenerative diseases in recent decades, treatment to delay disease progression is largely ineffective and is in urgent demand. The development of new strategies targeting these pathological features is a timely topic. It is important to note that most degenerative diseases are associated with the accumulation of specific misfolded proteins, which is facilitated by several common features of neurodegenerative diseases (including poor energy homeostasis and mitochondrial dysfunction). Adenosine is a purine nucleoside and neuromodulator in the brain. It is also an essential component of energy production pathways, cellular metabolism, and gene regulation in brain cells. The levels of intracellular and extracellular adenosine are thus tightly controlled by a handful of proteins (including adenosine metabolic enzymes and transporters) to maintain proper adenosine homeostasis. Notably, disruption of adenosine homeostasis in the brain under various pathophysiological conditions has been documented. In the past two decades, adenosine receptors (particularly A1 and A2A adenosine receptors) have been actively investigated as important drug targets in major degenerative diseases. Unfortunately, except for an A2A antagonist (istradefylline) administered as an adjuvant treatment with levodopa for Parkinson's disease, no effective drug based on adenosine receptors has been developed for neurodegenerative diseases. In this review, we summarize the emerging findings on proteins involved in the control of adenosine homeostasis in the brain and discuss the challenges and future prospects for the development of new therapeutic treatments for neurodegenerative diseases and their associated disorders based on the understanding of adenosine homeostasis.
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Verkhratsky A, Sun D, Tanaka J. Snapshot of microglial physiological functions. Neurochem Int 2021; 144:104960. [PMID: 33460721 DOI: 10.1016/j.neuint.2021.104960] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 01/11/2021] [Indexed: 02/08/2023]
Abstract
Microglia as a defensive arm of the nervous system emerged early in evolution. The surveilling microglia with motile and ramified processes are the main phenotype in the healthy CNS; the surveilling microglial patrol neuronal somata, dendrites, dendritic spines and axons. Increasing evidence suggests that microglia play fundamental roles in development, maturation and ageing of the brain, as well as contribute to a variety of physiological brain processes including sleep and circadian rhythm. Physiological state of microglia is tightly regulated by brain microenvironment and controlled by a sophisticated system of receptors and signalling cascades including ionotropic and metabotropic purinoceptors, pattern-recognition receptors, and receptors for chemokines and cytokines. Microglia also utilise ion channels and transporters in regulating ionic homeostasis and various aspects of microglial function. The major ion transporters expressed by microglia include Na+/H+ exchanger 1 and Na+/Ca2+ exchangers, which are involved in regulation of pHi and Ca2+ homeostasis during microglial physiological responses. Microglial cells control development, maturation and plasticity of neuronal ensembles through controlled physiological phagocytosis of synapses or synaptic fragments - processes known as synaptic pruning and trogocytosis. This special issue on "Physiological roles of microglia" is an assembly of papers written by the leading experts in this research field. We start this special issue with this snapshot of microglial physiological functions as a prelude to the indepth discussion of microglia in physiological processes in the nervous system.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK; Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain.
| | - Dandan Sun
- Department of Neurology and Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh, Pittsburgh, PA, 15213, USA; Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, PA, 15213, USA.
| | - Junya Tanaka
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, Ehime University, Ehime, 791-0295, Japan.
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Spanoghe J, Larsen LE, Craey E, Manzella S, Van Dycke A, Boon P, Raedt R. The Signaling Pathways Involved in the Anticonvulsive Effects of the Adenosine A 1 Receptor. Int J Mol Sci 2020; 22:ijms22010320. [PMID: 33396826 PMCID: PMC7794785 DOI: 10.3390/ijms22010320] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 12/22/2020] [Accepted: 12/27/2020] [Indexed: 12/20/2022] Open
Abstract
Adenosine acts as an endogenous anticonvulsant and seizure terminator in the brain. Many of its anticonvulsive effects are mediated through the activation of the adenosine A1 receptor, a G protein-coupled receptor with a wide array of targets. Activating A1 receptors is an effective approach to suppress seizures. This review gives an overview of the neuronal targets of the adenosine A1 receptor focusing in particular on signaling pathways resulting in neuronal inhibition. These include direct interactions of G protein subunits, the adenyl cyclase pathway and the phospholipase C pathway, which all mediate neuronal hyperpolarization and suppression of synaptic transmission. Additionally, the contribution of the guanyl cyclase and mitogen-activated protein kinase cascades to the seizure-suppressing effects of A1 receptor activation are discussed. This review ends with the cautionary note that chronic activation of the A1 receptor might have detrimental effects, which will need to be avoided when pursuing A1 receptor-based epilepsy therapies.
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Affiliation(s)
- Jeroen Spanoghe
- 4Brain, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (J.S.); (L.E.L.); (E.C.); (S.M.); (P.B.)
| | - Lars E. Larsen
- 4Brain, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (J.S.); (L.E.L.); (E.C.); (S.M.); (P.B.)
| | - Erine Craey
- 4Brain, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (J.S.); (L.E.L.); (E.C.); (S.M.); (P.B.)
| | - Simona Manzella
- 4Brain, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (J.S.); (L.E.L.); (E.C.); (S.M.); (P.B.)
| | - Annelies Van Dycke
- Department of Neurology, General Hospital Sint-Jan Bruges, 8000 Bruges, Belgium;
| | - Paul Boon
- 4Brain, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (J.S.); (L.E.L.); (E.C.); (S.M.); (P.B.)
| | - Robrecht Raedt
- 4Brain, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (J.S.); (L.E.L.); (E.C.); (S.M.); (P.B.)
- Correspondence:
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Li P, Li X, Deng P, Wang D, Bai X, Li Y, Luo C, Belguise K, Wang X, Wei X, Xia Z, Yi B. Activation of adenosine A3 receptor reduces early brain injury by alleviating neuroinflammation after subarachnoid hemorrhage in elderly rats. Aging (Albany NY) 2020; 13:694-713. [PMID: 33253120 PMCID: PMC7835045 DOI: 10.18632/aging.202178] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 10/05/2020] [Indexed: 04/14/2023]
Abstract
The incidence of subarachnoid hemorrhage (SAH) and hazard ratio of death increase with age. Overactivation of microglia contributes to brain damage. This study aimed to investigate the effects of A3 adenosine receptors (A3R) activation on neurofunction and microglial phenotype polarization in the context of SAH in aged rats. The A3R agonist (CI-IB-MECA) and antagonist (MRS1523) were used in the SAH model. Microglia were cultured to mimic SAH in the presence or absence of CI-IB-MECA and/or siRNA for A3R. The neurofunction and status of the microglial phenotype were evaluated. The P38 inhibitor SB202190 and the STAT6 inhibitor AS1517499 were used to explore the signaling pathway. The results showed that SAH induced microglia to polarize to the M(LPS) phenotype both in vivo and in vitro. CI-IB-MECA distinctly skewed microglia towards the M(IL-4) phenotype and ameliorated neurological dysfunction, along with the downregulation of inflammatory cytokines. Knockdown of A3R or inhibition of P38 and/or STAT6 weakened the effects of CI-IB-MECA on microglial phenotypic shifting. Collectively, our findings suggest that activation of A3R exerted anti-inflammatory and neuroprotective effects by regulating microglial phenotype polarization through P38/STAT6 pathway and indicated that A3R agonists may be a promising therapeutic options for the treatment of brain injury after SAH.
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Affiliation(s)
- Peng Li
- Department of Anesthesia, Southwest Hospital, Third Military Medical University, Chongqing, China
- Department of Anesthesia, Sichuan Academy of Medical Sciences and Sichuan Provincial People’s Hospital, Chengdu, China
| | - Xiaojun Li
- Department of Anesthesia, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Peng Deng
- Department of Anesthesia, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Dandan Wang
- Department of Anesthesia, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Xuehong Bai
- Department of Anesthesia, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Yujie Li
- Department of Anesthesia, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Chunxia Luo
- Department of Neurology, Southwest Hospital, The Third Military Medical University, Chongqing, China
| | - Karine Belguise
- Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération (LBCMCP), University P. Sabatier, Toulouse Cedex 9, France
| | - Xiaobo Wang
- Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération (LBCMCP), University P. Sabatier, Toulouse Cedex 9, France
| | - Xinchuan Wei
- Department of Anesthesia, Sichuan Academy of Medical Sciences and Sichuan Provincial People’s Hospital, Chengdu, China
| | - Zhengyuan Xia
- Department of Anesthesiology, University of Hong Kong, Hong Kong SAR, China
- Department of Cerebrovascular Diseases, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Bin Yi
- Department of Anesthesia, Southwest Hospital, Third Military Medical University, Chongqing, China
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Microglia-neuron crosstalk: Signaling mechanism and control of synaptic transmission. Semin Cell Dev Biol 2019; 94:138-151. [PMID: 31112798 DOI: 10.1016/j.semcdb.2019.05.017] [Citation(s) in RCA: 110] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 04/17/2019] [Accepted: 05/16/2019] [Indexed: 12/13/2022]
Abstract
The continuous crosstalk between microglia and neurons is required for microglia housekeeping functions and contributes to brain homeostasis. Through these exchanges, microglia take part in crucial brain functions, including development and plasticity. The alteration of neuron-microglia communication contributes to brain disease states with consequences, ranging from synaptic function to neuronal survival. This review focuses on the signaling pathways responsible for neuron-microglia crosstalk, highlighting their physiological roles and their alteration or specific involvement in disease. In particular, we discuss studies, establishing how these signaling allow microglial cells to control relevant physiological functions during brain development, including synaptic formation and circuit refinement. In addition, we highlight how microglia and neurons interact functionally to regulate highly dynamical synaptic functions. Microglia are able to release several signaling molecules involved in the regulation of synaptic activity and plasticity. On the other side, molecules of neuronal origin control microglial processes motility in an activity-dependent manner. Indeed, the continuous crosstalk between microglia and neurons is required for the sensing and housekeeping functions of microglia and contributes to the maintenance of brain homeostasis and, particularly, to the sculpting of neuronal connections during development. These interactions lay on the delicate edge between physiological processes and homeostasis alteration in pathology and are themselves altered during neuroinflammation. The full description of these processes could be fundamental for understanding brain functioning in health and disease.
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11
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Elevated pre-activation basal level of nuclear NF-κB in native macrophages accelerates LPS-induced translocation of cytosolic NF-κB into the cell nucleus. Sci Rep 2019; 9:4563. [PMID: 30872589 PMCID: PMC6418260 DOI: 10.1038/s41598-018-36052-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 11/08/2018] [Indexed: 02/01/2023] Open
Abstract
Signaling via Toll-like receptor 4 (TLR4) in macrophages constitutes an essential part of the innate immune response to bacterial infections. Detailed and quantified descriptions of TLR4 signal transduction would help to understand and exploit the first-line response of innate immune defense. To date, most mathematical modelling studies were performed on transformed cell lines. However, properties of primary macrophages differ significantly. We therefore studied TLR4-dependent activation of NF-κB transcription factor in bone marrow-derived and peritoneal primary macrophages. We demonstrate that the kinetics of NF-κB phosphorylation and nuclear translocation induced by a wide range of bacterial lipopolysaccharide (LPS) concentrations in primary macrophages is much faster than previously reported for macrophage cell lines. We used a comprehensive combination of experiments and mathematical modeling to understand the mechanisms of this rapid response. We found that elevated basal NF-κB in the nuclei of primary macrophages is a mechanism increasing native macrophage sensitivity and response speed to the infection. Such pre-activated state of macrophages accelerates the NF-κB translocation kinetics in response to low agonist concentrations. These findings enabled us to refine and construct a new model combining both NF-κB phosphorylation and translocation processes and predict the existence of a negative feedback loop inactivating phosphorylated NF-κB.
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12
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Sepúlveda C, Palomo I, Fuentes E. Role of adenosine A2b receptor overexpression in tumor progression. Life Sci 2016; 166:92-99. [DOI: 10.1016/j.lfs.2016.10.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 10/01/2016] [Accepted: 10/07/2016] [Indexed: 02/07/2023]
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13
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The chemokine CXCL16 modulates neurotransmitter release in hippocampal CA1 area. Sci Rep 2016; 6:34633. [PMID: 27721466 PMCID: PMC5056385 DOI: 10.1038/srep34633] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 09/16/2016] [Indexed: 12/04/2022] Open
Abstract
Chemokines have several physio-pathological roles in the brain. Among them, the modulation of synaptic contacts and neurotransmission recently emerged as crucial activities during brain development, in adulthood, upon neuroinflammation and neurodegenerative diseases. CXCL16 is a chemokine normally expressed in the brain, where it exerts neuroprotective activity against glutamate-induced damages through cross communication with astrocytes and the involvement of the adenosine receptor type 3 (A3R) and the chemokine CCL2. Here we demonstrated for the first time that CXCL16 exerts a modulatory activity on inhibitory and excitatory synaptic transmission in CA1 area. We found that CXCL16 increases the frequency of the miniature inhibitory synaptic currents (mIPSCs) and the paired-pulse ratio (PPR) of evoked IPSCs (eIPSCs), suggesting a presynaptic modulation of the probability of GABA release. In addition, CXCL16 increases the frequency of the miniature excitatory synaptic currents (mEPSCs) and reduces the PPR of evoked excitatory transmission, indicating that the chemokine also modulates and enhances the release of glutamate. These effects were not present in the A3RKO mice and in WT slices treated with minocycline, confirming the involvement of A3 receptors and introducing microglial cells as key mediators of the modulatory activity of CXCL16 on neurons.
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Cunha RA. How does adenosine control neuronal dysfunction and neurodegeneration? J Neurochem 2016; 139:1019-1055. [PMID: 27365148 DOI: 10.1111/jnc.13724] [Citation(s) in RCA: 320] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 05/23/2016] [Accepted: 06/23/2016] [Indexed: 12/11/2022]
Abstract
The adenosine modulation system mostly operates through inhibitory A1 (A1 R) and facilitatory A2A receptors (A2A R) in the brain. The activity-dependent release of adenosine acts as a brake of excitatory transmission through A1 R, which are enriched in glutamatergic terminals. Adenosine sharpens salience of information encoding in neuronal circuits: high-frequency stimulation triggers ATP release in the 'activated' synapse, which is locally converted by ecto-nucleotidases into adenosine to selectively activate A2A R; A2A R switch off A1 R and CB1 receptors, bolster glutamate release and NMDA receptors to assist increasing synaptic plasticity in the 'activated' synapse; the parallel engagement of the astrocytic syncytium releases adenosine further inhibiting neighboring synapses, thus sharpening the encoded plastic change. Brain insults trigger a large outflow of adenosine and ATP, as a danger signal. A1 R are a hurdle for damage initiation, but they desensitize upon prolonged activation. However, if the insult is near-threshold and/or of short-duration, A1 R trigger preconditioning, which may limit the spread of damage. Brain insults also up-regulate A2A R, probably to bolster adaptive changes, but this heightens brain damage since A2A R blockade affords neuroprotection in models of epilepsy, depression, Alzheimer's, or Parkinson's disease. This initially involves a control of synaptotoxicity by neuronal A2A R, whereas astrocytic and microglia A2A R might control the spread of damage. The A2A R signaling mechanisms are largely unknown since A2A R are pleiotropic, coupling to different G proteins and non-canonical pathways to control the viability of glutamatergic synapses, neuroinflammation, mitochondria function, and cytoskeleton dynamics. Thus, simultaneously bolstering A1 R preconditioning and preventing excessive A2A R function might afford maximal neuroprotection. The main physiological role of the adenosine modulation system is to sharp the salience of information encoding through a combined action of adenosine A2A receptors (A2A R) in the synapse undergoing an alteration of synaptic efficiency with an increased inhibitory action of A1 R in all surrounding synapses. Brain insults trigger an up-regulation of A2A R in an attempt to bolster adaptive plasticity together with adenosine release and A1 R desensitization; this favors synaptotocity (increased A2A R) and decreases the hurdle to undergo degeneration (decreased A1 R). Maximal neuroprotection is expected to result from a combined A2A R blockade and increased A1 R activation. This article is part of a mini review series: "Synaptic Function and Dysfunction in Brain Diseases".
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Affiliation(s)
- Rodrigo A Cunha
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,FMUC-Faculty of Medicine, University of Coimbra, Coimbra, Portugal
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