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Gonçalves FQ, Matheus FC, Silva HB, Real JI, Rial D, Rodrigues RJ, Oses JP, Silva AC, Gonçalves N, Prediger RD, Tomé ÂR, Cunha RA. Increased ATP Release and Higher Impact of Adenosine A 2A Receptors on Corticostriatal Plasticity in a Rat Model of Presymptomatic Parkinson's Disease. Mol Neurobiol 2023; 60:1659-1674. [PMID: 36547848 PMCID: PMC9899190 DOI: 10.1007/s12035-022-03162-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 12/06/2022] [Indexed: 12/24/2022]
Abstract
Extracellular ATP can be a danger signal, but its role in striatal circuits afflicted in Parkinson's disease (PD) is unclear and was now investigated. ATP was particularly released at high stimulation intensities from purified striatal nerve terminals of mice, which were endowed with different ATP-P2 receptors (P2R), although P2R antagonists did not alter corticostriatal transmission or plasticity. Instead, ATP was extracellularly catabolized into adenosine through CD73 to activate adenosine A2A receptors (A2AR) modulating corticostriatal long-term potentiation (LTP) in mice. In the presymptomatic phase of a 6-hydroxydopamine rat model of PD, ATP release from striatal nerve terminals was increased and was responsible for a greater impact of CD73 and A2AR on corticostriatal LTP. These observations identify increased ATP release and ATP-derived formation of extracellular adenosine bolstering A2AR activation as a key pathway responsible for abnormal synaptic plasticity in circuits involved in the onset of PD motor symptoms. The translation of these findings to humans prompts extending the use of A2AR antagonists from only co-adjuvants of motor control in Parkinsonian patients to neuroprotective drugs delaying the onset of motor symptoms.
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Affiliation(s)
| | - Filipe C. Matheus
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal ,Department of Pharmacology, Center of Biological Sciences, Federal University of Santa Catarina (UFSC), Florianópolis, SC Brazil
| | - Henrique B. Silva
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Joana I. Real
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Daniel Rial
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Ricardo J. Rodrigues
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Jean-Pierre Oses
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - António C. Silva
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Nélio Gonçalves
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Rui D. Prediger
- Department of Pharmacology, Center of Biological Sciences, Federal University of Santa Catarina (UFSC), Florianópolis, SC Brazil
| | - Ângelo R. Tomé
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal ,Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Coimbra, Portugal
| | - Rodrigo A. Cunha
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal ,Faculty of Medicine, University of Coimbra, Coimbra, Portugal
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2
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Atif M, Alsrhani A, Naz F, Ullah MI, Alameen AAM, Imran M, Ejaz H. Adenosine A 2A receptor as a potential target for improving cancer immunotherapy. Mol Biol Rep 2022; 49:10677-10687. [PMID: 35752699 DOI: 10.1007/s11033-022-07685-7] [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: 04/26/2022] [Accepted: 06/07/2022] [Indexed: 11/29/2022]
Abstract
The adenosine nucleoside performs a wide range of actions on various human tissues by activating four cell surface receptors. Adenosine A2A receptors (A2ARs) are widely expressed in the striatum, olfactory bulb, platelets, leukocytes, spleen, and thymus. They promote vasodilatation, platelet antiaggregatory effect, protection from ischemic damage, and regulation of sensorimotor neurons in basal ganglia. Adenosine signaling plays a vital part in modulating in vivo pathophysiological responses. A2ARs are potent negative regulators of the antitumor and proinflammatory actions of activated T cells. This axis offers several therapeutic targets, the most important of which are A2ARs, HIF-1α, and CD39/CD73. Downregulation of this axis increases the effectiveness of modern immunotherapeutic approaches against cancer, such as αCTLA-4/αPD-1. These discoveries have led to a promising novel role of antagonists of A2AR in blocking angiogenesis in immunotherapy of cancer. A small molecule, AZD4635, strongly inhibits A2AR, lowering cancer volume and increasing anticancer immunity. Deletion of A2AR with CRISPR/Cas9 in both human and murine CAR T cells produces a substantial increase in the efficiency of these cells. This review asserts that inhibition of the adenosinergic pathway can boost antitumor immunity, and this axis should be a target for future immunotherapeutic strategies.
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Affiliation(s)
- Muhammad Atif
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Al Jouf, 72388, Saudi Arabia
| | - Abdullah Alsrhani
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Al Jouf, 72388, Saudi Arabia
| | - Farrah Naz
- Department of Pathology, Institute of Public Health, Lahore, Pakistan
| | - Muhammad Ikram Ullah
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Al Jouf, 72388, Saudi Arabia
| | - Ayman Ali Mohammed Alameen
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Al Jouf, 72388, Saudi Arabia
| | - Muhammad Imran
- Department of Food Science and Technology, University of Narowal, Narowal, Pakistan
| | - Hasan Ejaz
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Al Jouf, 72388, Saudi Arabia.
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3
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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: 27] [Impact Index Per Article: 6.8] [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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4
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Choudhury H, Chellappan DK, Sengupta P, Pandey M, Gorain B. Adenosine Receptors in Modulation of Central Nervous System Disorders. Curr Pharm Des 2020; 25:2808-2827. [PMID: 31309883 DOI: 10.2174/1381612825666190712181955] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 07/01/2019] [Indexed: 12/20/2022]
Abstract
The ubiquitous signaling nucleoside molecule, adenosine is found in different cells of the human body to provide its numerous pharmacological role. The associated actions of endogenous adenosine are largely dependent on conformational change of the widely expressed heterodimeric G-protein-coupled A1, A2A, A2B, and A3 adenosine receptors (ARs). These receptors are well conserved on the surface of specific cells, where potent neuromodulatory properties of this bioactive molecule reflected by its easy passage through the rigid blood-brainbarrier, to simultaneously act on the central nervous system (CNS). The minimal concentration of adenosine in body fluids (30-300 nM) is adequate to exert its neuromodulatory action in the CNS, whereas the modulatory effect of adenosine on ARs is the consequence of several neurodegenerative diseases. Modulatory action concerning the activation of such receptors in the CNS could be facilitated towards neuroprotective action against such CNS disorders. Our aim herein is to discuss briefly pathophysiological roles of adenosine on ARs in the modulation of different CNS disorders, which could be focused towards the identification of potential drug targets in recovering accompanying CNS disorders. Researches with active components with AR modulatory action have been extended and already reached to the bedside of the patients through clinical research in the improvement of CNS disorders. Therefore, this review consist of recent findings in literatures concerning the impact of ARs on diverse CNS disease pathways with the possible relevance to neurodegeneration.
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Affiliation(s)
- Hira Choudhury
- School of Pharmacy, International Medical University, Bukit Jalil, Kuala Lumpur, Malaysia
| | - Dinesh K Chellappan
- School of Pharmacy, International Medical University, Bukit Jalil, Kuala Lumpur, Malaysia
| | - Pallav Sengupta
- Department of Physiology, Faculty of Medicine, MA`HSA University, Kuala Lumpur, Malaysia
| | - Manisha Pandey
- School of Pharmacy, International Medical University, Bukit Jalil, Kuala Lumpur, Malaysia
| | - Bapi Gorain
- School of Pharmacy, Faculty of Health and Medical Science, Taylor's University, Subang Jaya, Selangor, Malaysia
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Loonen AJ, Wilffert B, Ivanova SA. Putative role of pharmacogenetics to elucidate the mechanism of tardive dyskinesia in schizophrenia. Pharmacogenomics 2019; 20:1199-1223. [PMID: 31686592 DOI: 10.2217/pgs-2019-0100] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Identifying biomarkers which can be used as a diagnostic tool is a major objective of pharmacogenetic studies. Most mental and many neurological disorders have a compiled multifaceted nature, which may be the reason why this endeavor has hitherto not been very successful. This is also true for tardive dyskinesia (TD), an involuntary movement complication of long-term treatment with antipsychotic drugs. The observed associations of specific gene variants with the prevalence and severity of a disorder can also be applied to try to elucidate the pathogenesis of the condition. In this paper, this strategy is used by combining pharmacogenetic knowledge with theories on the possible role of a dysfunction of specific cellular elements of neostriatal parts of the (dorsal) extrapyramidal circuits: various glutamatergic terminals, medium spiny neurons, striatal interneurons and ascending monoaminergic fibers. A peculiar finding is that genetic variants which would be expected to increase the neostriatal dopamine concentration are not associated with the prevalence and severity of TD. Moreover, modifying the sensitivity to glutamatergic long-term potentiation (and excitotoxicity) shows a relationship with levodopa-induced dyskinesia, but not with TD. Contrasting this, TD is associated with genetic variants that modify vulnerability to oxidative stress. Reducing the oxidative stress burden of medium spiny neurons may also be the mechanism behind the protective influence of 5-HT2 receptor antagonists. It is probably worthwhile to discriminate between neostriatal matrix and striosomal compartments when studying the mechanism of TD and between orofacial and limb-truncal components in epidemiological studies.
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Affiliation(s)
- Anton Jm Loonen
- Unit of PharmacoTherapy, Epidemiology & Economics, Groningen Research Institute of Pharmacy, University of Groningen, Antonius Deusinglaan 1, 9713AV Groningen, The Netherlands.,GGZ Westelijk Noord-Brabant, Hoofdlaan 8, 4661AA Halsteren, The Netherlands
| | - Bob Wilffert
- Unit of PharmacoTherapy, Epidemiology & Economics, Groningen Research Institute of Pharmacy, University of Groningen, Antonius Deusinglaan 1, 9713AV Groningen, The Netherlands.,Dept. of Clinical Pharmacy and Pharmacology, University Medical Centre Groningen, University of Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
| | - Svetlana A Ivanova
- Mental Health Research Institute, Tomsk National Research Medical Center of the Russian Academy of Sciences, Aleutskaya Street, 4, 634014 Tomsk, Russian Federation.,School of Non-Destructive Testing & Security, Division for Control and Diagnostics, National Research Tomsk Polytechnic University, Lenin Avenue, 30, 634050 Tomsk, Russian Federation.,Central Research Laboratory, Siberian State Medical University, Moscowski Trakt, 2, 634050 Tomsk, Russian Federation
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6
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Chen X, Zeng M, He D, Yan X, Chen H, Chen Y, Xia C, Wang J, Shen L, Zhu D, Wang J. Asthmatic Augmentation of Airway Vagal Activity Involves Decreased Central Expression and Activity of CD73 in Rats. ACS Chem Neurosci 2019; 10:2809-2822. [PMID: 30913879 DOI: 10.1021/acschemneuro.9b00023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The severity of asthma is closely related to the intensity of airway vagal activity; however, it is unclear how airway vagal activity is centrally augmented in asthma. Here we report that in an asthma model of male Sprague-Dawley rats, the expression and activity of ecto-5'-nucleotidase (CD73) were decreased in airway vagal centers, ATP concentration in cerebral spinal fluid was increased, and the inhibitory and excitatory airway vagal responses to intracisternally injected ATP (5 μmol) and CD73 inhibitor AMPCP (5 μmol), respectively, were attenuated. In airway vagal preganglionic neurons (AVPNs) identified in medullary slices of neonatal Sprague-Dawley rats, AMPCP (100 μmol·L-1) caused excitatory effects, as are shown in patch-clamp by depolarization, increased neuronal discharge, and facilitated spontaneous excitatory postsynaptic currents (sEPSCs). In contrast, exogenous ATP (100 μmol·L-1, 1 mmol·L-1) primarily caused inhibitory effects, which are similar to those induced by exogenous adenosine (100 μmol·L-1). Adenosine A1 receptor antagonist CPT (5 μmol·L-1) blocked the inhibition of sEPSCs induced by 100 μmol·L-1 exogenous ATP and that by 100 μmol·L-1 exogenous adenosine, whereas 50 μmol·L-1 CPT converted the inhibition of sEPSCs induced by 1 mmol·L-1 ATP to facilitation that was blocked by addition of P2X receptor antagonist PPADS (20 μmol·L-1). These results demonstrate that in rat, the sEPSCs of AVPNs are facilitated by extracellular ATP via activation of P2X receptors and inhibited by extracellular adenosine via activation of A1 receptors; in experimental asthma, decreased CD73 expression and activity in airway vagal centers contribute to the augmentation of airway vagal activity through imbalanced ATP/ADO modulation of AVPNs.
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Affiliation(s)
- Xingxin Chen
- Department of Neurobiology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Ming Zeng
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Ding He
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Xianxia Yan
- Department of Neurobiology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Hong Chen
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Yonghua Chen
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Chunmei Xia
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Jin Wang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Linlin Shen
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Danian Zhu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Jijiang Wang
- Department of Neurobiology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
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7
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Chavda S, Luthert PJ, Salt TE. P2X 7R modulation of visually evoked synaptic responses in the retina. Purinergic Signal 2016; 12:611-625. [PMID: 27393519 PMCID: PMC5123999 DOI: 10.1007/s11302-016-9522-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 06/24/2016] [Indexed: 10/29/2022] Open
Abstract
P2X7Rs are distributed throughout all layers of the retina, and thus, their localisation on various cell types puts into question their specific site(s) of action. Using a dark-adapted, ex vivo mouse retinal whole mount preparation, the present study aimed to characterise the effect of P2X7R activation on light-evoked, excitatory RGC ON-field excitatory post-synaptic potentials (fEPSPs) and on outer retinal electroretinogram (ERG) responses under comparable conditions. The pharmacologically isolated NMDA receptor-mediated RGC ON-fEPSP was reduced in the presence of BzATP, an effect which was significantly attenuated by A438079 and other selective P2X7R antagonists A804598 or AF27139. In physiological Krebs medium, BzATP induced a significant potentiation of the ERG a-wave, with a concomitant reduction in the b-wave and the power of the oscillatory potentials. Conversely, in the pharmacologically modified Mg2+-free perfusate, BzATP reduced both the a-wave and b-wave. The effects of BzATP on the ERG components were suppressed by A438079. A role for P2X7R function in visual processing in both the inner and outer retina under physiological conditions remains controversial. The ON-fEPSP was significantly reduced in the presence of A804598 but not by A438079 or AF27139. Furthermore, A438079 did not have any effect on the ERG components in physiological Krebs but potentiated and reduced the a-wave and b-wave, respectively, when applied to the pharmacologically modified medium. Therefore, activation of P2X7Rs affects the function in the retinal ON pathway. The presence of a high concentration of extracellular ATP would most likely contribute to the modulation of visual transmission in the retina in the pathophysiological microenvironment.
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Affiliation(s)
- Seetal Chavda
- Visual Neuroscience, UCL Institute of Ophthalmology, London, EC1V 9EL, UK
| | - Philip J Luthert
- Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, EC1V 9EL, UK.,NIHR Biomedical Research Centre in Ophthalmology, London, EC1V 9EL, UK
| | - Thomas E Salt
- Visual Neuroscience, UCL Institute of Ophthalmology, London, EC1V 9EL, UK.
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8
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Köles L, Kató E, Hanuska A, Zádori ZS, Al-Khrasani M, Zelles T, Rubini P, Illes P. Modulation of excitatory neurotransmission by neuronal/glial signalling molecules: interplay between purinergic and glutamatergic systems. Purinergic Signal 2015; 12:1-24. [PMID: 26542977 DOI: 10.1007/s11302-015-9480-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 10/26/2015] [Indexed: 12/29/2022] Open
Abstract
Glutamate is the main excitatory neurotransmitter of the central nervous system (CNS), released both from neurons and glial cells. Acting via ionotropic (NMDA, AMPA, kainate) and metabotropic glutamate receptors, it is critically involved in essential regulatory functions. Disturbances of glutamatergic neurotransmission can be detected in cognitive and neurodegenerative disorders. This paper summarizes the present knowledge on the modulation of glutamate-mediated responses in the CNS. Emphasis will be put on NMDA receptor channels, which are essential executive and integrative elements of the glutamatergic system. This receptor is crucial for proper functioning of neuronal circuits; its hypofunction or overactivation can result in neuronal disturbances and neurotoxicity. Somewhat surprisingly, NMDA receptors are not widely targeted by pharmacotherapy in clinics; their robust activation or inhibition seems to be desirable only in exceptional cases. However, their fine-tuning might provide a promising manipulation to optimize the activity of the glutamatergic system and to restore proper CNS function. This orchestration utilizes several neuromodulators. Besides the classical ones such as dopamine, novel candidates emerged in the last two decades. The purinergic system is a promising possibility to optimize the activity of the glutamatergic system. It exerts not only direct and indirect influences on NMDA receptors but, by modulating glutamatergic transmission, also plays an important role in glia-neuron communication. These purinergic functions will be illustrated mostly by depicting the modulatory role of the purinergic system on glutamatergic transmission in the prefrontal cortex, a CNS area important for attention, memory and learning.
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Affiliation(s)
- László Köles
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4, Budapest, 1089, Hungary.
| | - Erzsébet Kató
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4, Budapest, 1089, Hungary
| | - Adrienn Hanuska
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4, Budapest, 1089, Hungary
| | - Zoltán S Zádori
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4, Budapest, 1089, Hungary
| | - Mahmoud Al-Khrasani
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4, Budapest, 1089, Hungary
| | - Tibor Zelles
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4, Budapest, 1089, Hungary
| | - Patrizia Rubini
- Rudolf-Boehm-Institute of Pharmacology and Toxicology, University of Leipzig, 04107, Leipzig, Germany
| | - Peter Illes
- Rudolf-Boehm-Institute of Pharmacology and Toxicology, University of Leipzig, 04107, Leipzig, Germany.
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Sáez-Orellana F, Godoy PA, Bastidas CY, Silva-Grecchi T, Guzmán L, Aguayo LG, Fuentealba J. ATP leakage induces P2XR activation and contributes to acute synaptic excitotoxicity induced by soluble oligomers of β-amyloid peptide in hippocampal neurons. Neuropharmacology 2015; 100:116-23. [PMID: 25896766 DOI: 10.1016/j.neuropharm.2015.04.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 03/10/2015] [Accepted: 04/07/2015] [Indexed: 01/06/2023]
Abstract
Recent studies suggest that the toxic effects of Aβ can be attributed to its capability to insert in membranes and form pore-like structures, which are permeable to cations and molecules such as ATP. Our working hypothesis is that Aβ increases extracellular ATP causing activation of P2X receptors and potentiating excitatory synaptic activity. We found that soluble oligomers of β-amyloid peptide increased cytosolic Ca(2+) 4-fold above control (415 ± 28% of control). Also, ATP leakage (157 ± 10% of control) was independent of extracellular Ca(2+), suggesting that ATP traveled from the cytosol through an Aβ pore-mediated efflux and not from exocytotic mechanisms. The subsequent activation of P2XR by ATP can contribute to the cytosolic Ca(2+) increase observed with Aβ. Additionally, we found that β-amyloid oligomers bind preferentially to excitatory neurons inducing an increase in excitatory synaptic current frequency (248.1 ± 32.7%) that was blocked by the use of P2XR antagonists such as PPADS (Aβ + PPADS: 110.9 ± 18.35%) or Apyrase plus DPCPX (Aβ + inhibitors: 98.97 ± 17.4%). Taken together, we suggest that Aβ induces excitotoxicity by binding preferentially to excitatory neuron membranes forming a non-selective pore and by increasing intracellular calcium by itself and through P2XR activation by extracellular ATP leading to an augmention in mEPSC activity. All these effects were blocked with a non-specific P2XR antagonist, indicating that part of the neurotoxicity of Aβ is mediated by P2XR activation and facilitation of excitatory neurotransmitter release. These findings suggest that P2XR can be considered as a potential new target for the development of drugs or pharmacological tools to treat Alzheimer's disease. This article is part of the Special Issue entitled 'Synaptopathy--from Biology to Therapy'.
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Affiliation(s)
- F Sáez-Orellana
- Laboratory of Screening of Neuroactive Compound, Physiology Department, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile
| | - P A Godoy
- Laboratory of Screening of Neuroactive Compound, Physiology Department, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile
| | - C Y Bastidas
- Laboratory of Screening of Neuroactive Compound, Physiology Department, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile
| | - T Silva-Grecchi
- Laboratory of Screening of Neuroactive Compound, Physiology Department, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile
| | - L Guzmán
- Neurophysiology Laboratory, Physiology Department, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile
| | - L G Aguayo
- Neurophysiology Laboratory, Physiology Department, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile
| | - J Fuentealba
- Laboratory of Screening of Neuroactive Compound, Physiology Department, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile; Center for Advanced Research on Biomedicine (CIAB-UdeC), Physiology Department, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile.
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10
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Sachdeva S, Gupta M. Adenosine and its receptors as therapeutic targets: An overview. Saudi Pharm J 2013; 21:245-53. [PMID: 23960840 PMCID: PMC3744929 DOI: 10.1016/j.jsps.2012.05.011] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 05/31/2012] [Indexed: 12/14/2022] Open
Abstract
The main goal of the authors is to present an overview of adenosine and its receptors, which are G-protein coupled receptors. The four known adenosine receptor subtypes are discussed along with the therapeutic potential indicating that these receptors can serve as targets for various dreadful diseases.
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Affiliation(s)
| | - Monika Gupta
- ASBASJSM College of Pharmacy, Bela, Ropar, India
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