201
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Mohamed RA, Agha AM, Abdel-Rahman AA, Nassar NN. Role of adenosine A2A receptor in cerebral ischemia reperfusion injury: Signaling to phosphorylated extracellular signal-regulated protein kinase (pERK1/2). Neuroscience 2015; 314:145-59. [PMID: 26642806 DOI: 10.1016/j.neuroscience.2015.11.059] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 11/02/2015] [Accepted: 11/25/2015] [Indexed: 12/11/2022]
Abstract
Following brain ischemia reperfusion (IR), the dramatic increase in adenosine activates A2AR to induce further neuronal damage. Noteworthy, A2A antagonists have proven efficacious in halting IR injury, however, the detailed downstream signaling remains elusive. To this end, the present study aimed to investigate the possible involvement of phospho-extracellular signal-regulated kinase (pERK1/2) pathway in mediating protection afforded by the central A2A blockade. Male Wistar rats (250-270 g) subjected to bilateral carotid occlusion for 45 min followed by a 24-h reperfusion period showed increased infarct size corroborating histopathological damage, memory impairment and motor incoordination as well as increased locomotor activity. Those events were mitigated by the unilateral intrahippocampal administration of the selective A2A antagonist SCH58261 via a decrease in pERK1/2 downstream from diacyl glycerol (DAG) signaling. Consequent to pERK1/2 inhibition, reduced hippocampal microglial activation, glial tumor necrosis factor-alpha (TNF-α) and brain-derived neurotropic factor (BDNF) expression, glutamate (Glu), inducible nitric oxide synthase (iNOS) and thiobarbituric acid reactive substances (TBARS) were evident in animals receiving SCH58261. Additionally, the anti-inflammatory cytokine interleukin-10 (IL-10) increased following nuclear factor (erythroid-derived 2)-like 2 (Nrf-2). Taken all together, these events suppressed apoptotic pathways via a reduction in cytochrome c (Cyt. c) as well as caspase-3 supporting a crucial role for pERK1/2 inhibition in consequent reduction of inflammatory and excitotoxic cascades as well as correction of the redox imbalance.
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Affiliation(s)
- R A Mohamed
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Cairo, Egypt.
| | - A M Agha
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Cairo, Egypt.
| | - A A Abdel-Rahman
- Department of Pharmacology and Toxicology, Brody School of Medicine, East Carolina University, NC, USA.
| | - N N Nassar
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Cairo, Egypt.
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202
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Stockwell J, Chen Z, Niazi M, Nosib S, Cayabyab FS. Protein phosphatase role in adenosine A1 receptor-induced AMPA receptor trafficking and rat hippocampal neuronal damage in hypoxia/reperfusion injury. Neuropharmacology 2015; 102:254-65. [PMID: 26626486 DOI: 10.1016/j.neuropharm.2015.11.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 11/19/2015] [Accepted: 11/21/2015] [Indexed: 12/19/2022]
Abstract
Adenosine signaling via A1 receptor (A1R) and A2A receptor (A2AR) has shown promise in revealing potential targets for neuroprotection in cerebral ischemia. We recently showed a novel mechanism by which A1R activation with N(6)-cyclopentyl adenosine (CPA) induced GluA1 and GluA2 AMPA receptor (AMPAR) endocytosis and adenosine-induced persistent synaptic depression (APSD) in rat hippocampus. This study further investigates the mechanism of A1R-mediated AMPAR internalization and hippocampal slice neuronal damage through activation of protein phosphatase 1 (PP1), 2A (PP2A), and 2B (PP2B) using electrophysiological, biochemical and imaging techniques. Following prolonged A1R activation, GluA2 internalization was selectively blocked by PP2A inhibitors (okadaic acid and fostriecin), whereas inhibitors of PP2A, PP1 (tautomycetin), and PP2B (FK506) all prevented GluA1 internalization. Additionally, GluA1 phosphorylation at Ser831 and Ser845 was reduced after prolonged A1R activation in hippocampal slices. PP2A inhibitors nullified A1R-mediated downregulation of pSer845-GluA1, while PP1 and PP2B inhibitors prevented pSer831-GluA1 downregulation. Each protein phosphatase inhibitor also blunted CPA-induced synaptic depression and APSD. We then tested whether A1R-mediated changes in AMPAR trafficking and APSD contribute to hypoxia-induced neuronal injury. Hypoxia (20 min) induced A1R-mediated internalization of both AMPAR subunits, and subsequent normoxic reperfusion (45 min) increased GluA1 but persistently reduced GluA2 surface expression. Neuronal damage after hypoxia-reperfusion injury was significantly blunted by pre-incubation with the above protein phosphatase inhibitors. Together, these data suggest that A1R-mediated protein phosphatase activation causes persistent synaptic depression by downregulating GluA2-containing AMPARs; this previously undefined role of A1R stimulation in hippocampal neuronal damage represents a novel therapeutic target in cerebral ischemic damage.
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Affiliation(s)
- Jocelyn Stockwell
- Department of Surgery, Neuroscience Research Group, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
| | - Zhicheng Chen
- Department of Surgery, Neuroscience Research Group, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
| | - Mina Niazi
- Department of Surgery, Neuroscience Research Group, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
| | - Siddarth Nosib
- Department of Surgery, Neuroscience Research Group, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
| | - Francisco S Cayabyab
- Department of Surgery, Neuroscience Research Group, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
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203
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Purine nucleosides in neuroregeneration and neuroprotection. Neuropharmacology 2015; 104:226-42. [PMID: 26577017 DOI: 10.1016/j.neuropharm.2015.11.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 11/05/2015] [Accepted: 11/06/2015] [Indexed: 12/20/2022]
Abstract
In the present review, we stress the importance of the purine nucleosides, adenosine and guanosine, in protecting the nervous system, both centrally and peripherally, via activation of their receptors and intracellular signalling mechanisms. A most novel part of the review focus on the mechanisms of neuronal regeneration that are targeted by nucleosides, including a recently identified action of adenosine on axonal growth and microtubule dynamics. Discussion on the role of the purine nucleosides transversally with the most established neurotrophic factors, e.g. brain derived neurotrophic factor (BDNF), glial derived neurotrophic factor (GDNF), is also focused considering the intimate relationship between some adenosine receptors, as is the case of the A2A receptors, and receptors for neurotrophins. This article is part of the Special Issue entitled 'Purines in Neurodegeneration and Neuroregeneration'.
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204
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Kutuzov N, Gulin A, Lyaskovskiy V, Nadtochenko V, Maksimov G. ATP-Mediated Compositional Change in Peripheral Myelin Membranes: A Comparative Raman Spectroscopy and Time-Of-Flight Secondary Ion Mass Spectrometry Study. PLoS One 2015; 10:e0142084. [PMID: 26544552 PMCID: PMC4636249 DOI: 10.1371/journal.pone.0142084] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 10/16/2015] [Indexed: 12/20/2022] Open
Abstract
In the present paper we addressed a mechanism of the myelin reorganization initiated by extracellular ATP and adenosine in sciatic nerves of the frog Rana temporaria. In combination with Raman microspectroscopy, allowing noninvasive live-cell measurements, we employed time-of-flight secondary ion mass spectrometry (TOF-SIMS) to follow the underlying changes in chemical composition of myelin membranes triggered by the purinergic agents. The simultaneous increase in lipid ordering degree, decrease in membrane fluidity and the degree of fatty acid unsaturation were induced by both ATP and adenosine. Mass spectrometry measurements revealed that ATP administration also led to the marked elevation of membrane cholesterol and decrease of phosphotidylcholine amounts. Vesicular lipid transport pathways are considered as possible mechanisms of compositional and structural changes of myelin.
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Affiliation(s)
- Nikolay Kutuzov
- Biophysics Department, Biological Faculty, Moscow State University, Leninskie gory 1/12, Moscow, Russian Federation, 119991
- * E-mail:
| | - Alexander Gulin
- N.N. Semenov Institute of Chemical Physics, RAS, Kosigin str. 4, Moscow, Russian Federation, 119991
- Chemistry Faculty, Moscow State University, Leninskie Gory 1–3, Moscow, Russian Federation, 119991
| | - Vladimir Lyaskovskiy
- All-Russian Research Institute for Optical and Physical Measurements, Ozernaya 46, Moscow, Russian Federation, 119361
| | - Victor Nadtochenko
- N.N. Semenov Institute of Chemical Physics, RAS, Kosigin str. 4, Moscow, Russian Federation, 119991
- Chemistry Faculty, Moscow State University, Leninskie Gory 1–3, Moscow, Russian Federation, 119991
- Moscow Institute of Physics and Technology State University, Institutskiy per. 9, Dolgoprudny, Moscow Region, Russian Federation, 141700
- Institute of Problems of Chemical Physics RAS, Academician Semenov avenue 1, Chernogolovka, Moscow region, Russian Federation, 142432
| | - Georgy Maksimov
- Biophysics Department, Biological Faculty, Moscow State University, Leninskie gory 1/12, Moscow, Russian Federation, 119991
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205
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Ferreira DG, Batalha VL, Vicente Miranda H, Coelho JE, Gomes R, Gonçalves FQ, Real JI, Rino J, Albino-Teixeira A, Cunha RA, Outeiro TF, Lopes LV. Adenosine A2AReceptors Modulate α-Synuclein Aggregation and Toxicity. Cereb Cortex 2015; 27:718-730. [DOI: 10.1093/cercor/bhv268] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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206
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Boison D, Aronica E. Comorbidities in Neurology: Is adenosine the common link? Neuropharmacology 2015; 97:18-34. [PMID: 25979489 PMCID: PMC4537378 DOI: 10.1016/j.neuropharm.2015.04.031] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Revised: 04/24/2015] [Accepted: 04/27/2015] [Indexed: 12/13/2022]
Abstract
Comorbidities in Neurology represent a major conceptual and therapeutic challenge. For example, temporal lobe epilepsy (TLE) is a syndrome comprised of epileptic seizures and comorbid symptoms including memory and psychiatric impairment, depression, and sleep dysfunction. Similarly, Alzheimer's disease (AD), Parkinson's disease (PD), and Amyotrophic Lateral Sclerosis (ALS) are accompanied by various degrees of memory dysfunction. Patients with AD have an increased likelihood for seizures, whereas all four conditions share certain aspects of psychosis, depression, and sleep dysfunction. This remarkable overlap suggests common pathophysiological mechanisms, which include synaptic dysfunction and synaptotoxicity, as well as glial activation and astrogliosis. Astrogliosis is linked to synapse function via the tripartite synapse, but astrocytes also control the availability of gliotransmitters and adenosine. Here we will specifically focus on the 'adenosine hypothesis of comorbidities' implying that astrocyte activation, via overexpression of adenosine kinase (ADK), induces a deficiency in the homeostatic tone of adenosine. We present evidence from patient-derived samples showing astrogliosis and overexpression of ADK as common pathological hallmark of epilepsy, AD, PD, and ALS. We discuss a transgenic 'comorbidity model', in which brain-wide overexpression of ADK and resulting adenosine deficiency produces a comorbid spectrum of seizures, altered dopaminergic function, attentional impairment, and deficits in cognitive domains and sleep regulation. We conclude that dysfunction of adenosine signaling is common in neurological conditions, that adenosine dysfunction can explain co-morbid phenotypes, and that therapeutic adenosine augmentation might be effective for the treatment of comorbid symptoms in multiple neurological conditions.
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Affiliation(s)
- Detlev Boison
- Robert Stone Dow Neurobiology Laboratories, Legacy Research Institute, Portland, OR 97232, USA.
| | - Eleonora Aronica
- Department of (Neuro)Pathology, Academic Medical Center and Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, The Netherlands; Stichting Epilepsie Instellingen (SEIN) Nederland, Heemstede, The Netherlands
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207
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Neth K, Lucio M, Walker A, Zorn J, Schmitt-Kopplin P, Michalke B. Changes in Brain Metallome/Metabolome Pattern due to a Single i.v. Injection of Manganese in Rats. PLoS One 2015; 10:e0138270. [PMID: 26383269 PMCID: PMC4575095 DOI: 10.1371/journal.pone.0138270] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 08/27/2015] [Indexed: 12/20/2022] Open
Abstract
Exposure to high concentrations of Manganese (Mn) is known to potentially induce an accumulation in the brain, leading to a Parkinson related disease, called manganism. Versatile mechanisms of Mn-induced brain injury are discussed, with inactivation of mitochondrial defense against oxidative stress being a major one. So far, studies indicate that the main Mn-species entering the brain are low molecular mass (LMM) compounds such as Mn-citrate. Applying a single low dose MnCl2 injection in rats, we observed alterations in Mn-species pattern within the brain by analysis of aqueous brain extracts by size-exclusion chromatography—inductively coupled plasma mass spectrometry (SEC-ICP-MS). Additionally, electrospray ionization—ion cyclotron resonance-Fourier transform-mass spectrometry (ESI-ICR/FT-MS) measurement of methanolic brain extracts revealed a comprehensive analysis of changes in brain metabolisms after the single MnCl2 injection. Major alterations were observed for amino acid, fatty acid, glutathione, glucose and purine/pyrimidine metabolism. The power of this metabolomic approach is the broad and detailed overview of affected brain metabolisms. We also correlated results from the metallomic investigations (Mn concentrations and Mn-species in brain) with the findings from metabolomics. This strategy might help to unravel the role of different Mn-species during Mn-induced alterations in brain metabolism.
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Affiliation(s)
- Katharina Neth
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München—German Research Center for Environment and Health (GmbH), Ingolstädter Landstrasse 1, D-85764, Neuherberg, Germany
- * E-mail:
| | - Marianna Lucio
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München—German Research Center for Environment and Health (GmbH), Ingolstädter Landstrasse 1, D-85764, Neuherberg, Germany
| | - Alesia Walker
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München—German Research Center for Environment and Health (GmbH), Ingolstädter Landstrasse 1, D-85764, Neuherberg, Germany
| | - Julia Zorn
- Research Unit Comparative Medicine, Helmholtz Zentrum München—German Research Center for Environment and Health (GmbH), Ingolstädter Landstrasse 1, D-85764, Neuherberg, Germany
| | - Philippe Schmitt-Kopplin
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München—German Research Center for Environment and Health (GmbH), Ingolstädter Landstrasse 1, D-85764, Neuherberg, Germany
- Chair of Analytical Food Chemistry, Technische Universität München, Alte Akademie 10, D- 85354, Freising-Weihenstephan, Germany
| | - Bernhard Michalke
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München—German Research Center for Environment and Health (GmbH), Ingolstädter Landstrasse 1, D-85764, Neuherberg, Germany
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208
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Modulatory effects of inosine, guanosine and uridine on lipopolysaccharide-evoked increase in spike-wave discharge activity in Wistar Albino Glaxo/Rijswijk rats. Brain Res Bull 2015; 118:46-57. [DOI: 10.1016/j.brainresbull.2015.09.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 09/05/2015] [Accepted: 09/07/2015] [Indexed: 12/20/2022]
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209
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Pourcher E, Huot P. Adenosine 2A Receptor Antagonists for the Treatment of Motor Symptoms in Parkinson's Disease. Mov Disord Clin Pract 2015; 2:331-340. [PMID: 30363540 DOI: 10.1002/mdc3.12187] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 03/20/2015] [Accepted: 03/25/2015] [Indexed: 12/20/2022] Open
Abstract
Background Treatment of motor fluctuations in Parkinson's disease (PD) remains an unmet challenge. Adenosine 2A (A2A) receptors are located along the indirect pathway and represent a potential target to enhance l-3,4-dihydroxyphenylalanine (l-DOPA) antiparkinsonian action. Methods This article summarizes the preclinical and clinical literature on A2A antagonists in PD, with a specific focus on their effect on off time, on time, and dyskinesia. Findings Several A2A receptor antagonists have been tested in preclinical studies and clinical trials. In preclinical studies, A2A antagonists enhanced l-DOPA antiparkinsonian action without exacerbating dyskinesia, but A2A antagonists were generally administered in combination with a subthreshold dose of l-DOPA, which is different to the paradigms used in clinical trials, where A2A antagonists were usually added to an optimal antiparkinsonian regimen. In clinical settings, A2A antagonists generally reduced duration of off time, by as much as 25% in some studies. The effect of on time duration is less clear, and in a few studies an exacerbation of dyskinesia was reported. Two A2A antagonists have been tested in phase III settings: istradefylline and preladenant. Istradefylline was effective in two phase III trials, but ineffective in another; the drug has been commercially available in Japan since 2013. In contrast, preladenant was ineffective in a phase III trial and the drug was discontinued. A phase III study with tozadenant will begin in 2015; the drug was effective at reducing off time in a phase IIb study. Other A2A antagonists are in development at the preclinical and early clinical levels.
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Affiliation(s)
- Emmanuelle Pourcher
- Clinique Sainte-Anne Mémoire et Mouvement Faculty of Medicine Laval University Quebec City Quebec Canada.,Centre Thématique de Recherche en Neuroscience Laval University Quebec City Quebec Canada
| | - Philippe Huot
- Department of Pharmacology Faculty of Medicine University of Montreal Montreal Quebec Canada.,Division of Neurology Centre Hospitalier de l'Université de Montréal Montreal Quebec Canada
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210
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Unpredictable Chronic Stress Alters Adenosine Metabolism in Zebrafish Brain. Mol Neurobiol 2015; 53:2518-28. [PMID: 26081145 DOI: 10.1007/s12035-015-9270-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 05/28/2015] [Indexed: 12/20/2022]
Abstract
Stress is considered a risk factor for several human disorders. Despite the broad knowledge of stress responses in mammals, data on the relationship between unpredictable chronic stress (UCS) and its effects on purinergic signaling are limited. ATP hydrolysis by ectonucleotidases is an important source of adenosine, and adenosine deaminase (ADA) contributes to the control of the nucleoside concentrations. Considering that some stress models could affect signaling systems, the objective of this study was to investigate whether UCS alters ectonucleotidase and ADA pathway in zebrafish brain. Additionally, we analyzed ATP metabolism as well as ada1, ada2.1, ada2.2, adaL, and adaasi gene expression in zebrafish brain. Our results have demonstrated that UCS did not alter ectonucleotidase and soluble ADA activities. However, ecto-ADA activity was significantly decreased (26.8%) in brain membranes of animals exposed to UCS when compared to the control group. Quantitative reverse transcription PCR (RT-PCR) analysis did not show significant changes on ADA gene expression after the UCS exposure. The brain ATP metabolism showed a marked increase in adenosine levels (ADO) in animals exposed to UCS. These data suggest an increase on extracellular adenosine levels in zebrafish brain. Since this nucleoside has neuromodulatory and anxiolytic effects, changes in adenosine levels could play a role in counteracting the stress, which could be related to a compensatory mechanism in order to restore the homeostasis.
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211
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Madeira MH, Elvas F, Boia R, Gonçalves FQ, Cunha RA, Ambrósio AF, Santiago AR. Adenosine A2AR blockade prevents neuroinflammation-induced death of retinal ganglion cells caused by elevated pressure. J Neuroinflammation 2015; 12:115. [PMID: 26054642 PMCID: PMC4465153 DOI: 10.1186/s12974-015-0333-5] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 05/27/2015] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Elevated intraocular pressure (IOP) is a major risk factor for glaucoma, a degenerative disease characterized by the loss of retinal ganglion cells (RGCs). There is clinical and experimental evidence that neuroinflammation is involved in the pathogenesis of glaucoma. Since the blockade of adenosine A2A receptor (A2AR) confers robust neuroprotection and controls microglia reactivity in the brain, we now investigated the ability of A2AR blockade to control the reactivity of microglia and neuroinflammation as well as RGC loss in retinal organotypic cultures exposed to elevated hydrostatic pressure (EHP) or lipopolysaccharide (LPS). METHODS Retinal organotypic cultures were either incubated with LPS (3 μg/mL), to elicit a pro-inflammatory response, or exposed to EHP (+70 mmHg), to mimic increased IOP, for 4 or 24 h, in the presence or absence of the A2AR antagonist SCH 58261 (50 nM). A2AR expression, microglial reactivity and neuroinflammatory response were evaluated by immunohistochemistry, quantitative PCR (qPCR) and enzyme-linked immunosorbent assay (ELISA). RGC loss was assessed by immunohistochemistry. In order to investigate the contribution of pro-inflammatory mediators to RGC loss, the organotypic retinal cultures were incubated with rabbit anti-tumour necrosis factor (TNF) (2 μg/mL) and goat anti-interleukin-1β (IL-1β) (1 μg/mL) antibodies. RESULTS We report that the A2AR antagonist (SCH 58261) prevented microglia reactivity, increase in pro-inflammatory mediators as well as RGC loss upon exposure to either LPS or EHP. Additionally, neutralization of TNF and IL-1β prevented RGC loss induced by LPS or EHP. CONCLUSIONS This work demonstrates that A2AR blockade confers neuroprotection to RGCs by controlling microglia-mediated retinal neuroinflammation and prompts the hypothesis that A2AR antagonists may be a novel therapeutic option to manage glaucomatous disorders.
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Affiliation(s)
- Maria H Madeira
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548, Coimbra, Portugal. .,CNC.IBILI, University of Coimbra, 3004-517, Coimbra, Portugal.
| | - Filipe Elvas
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548, Coimbra, Portugal.
| | - Raquel Boia
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548, Coimbra, Portugal. .,CNC.IBILI, University of Coimbra, 3004-517, Coimbra, Portugal.
| | - Francisco Q Gonçalves
- CNC.IBILI, University of Coimbra, 3004-517, Coimbra, Portugal. .,CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517, Coimbra, Portugal.
| | - Rodrigo A Cunha
- CNC.IBILI, University of Coimbra, 3004-517, Coimbra, Portugal. .,CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517, Coimbra, Portugal. .,Faculty of Medicine, University of Coimbra, 3000-548, Coimbra, Portugal.
| | - António Francisco Ambrósio
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548, Coimbra, Portugal. .,CNC.IBILI, University of Coimbra, 3004-517, Coimbra, Portugal. .,Association for Innovation and Biomedical Research on Light (AIBILI), 3000-548, Coimbra, Portugal.
| | - Ana Raquel Santiago
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548, Coimbra, Portugal. .,CNC.IBILI, University of Coimbra, 3004-517, Coimbra, Portugal. .,Association for Innovation and Biomedical Research on Light (AIBILI), 3000-548, Coimbra, Portugal. .,Faculty of Medicine, University of Coimbra, 3000-548, Coimbra, Portugal. .,IBILI, Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, 3004-548, Coimbra, Portugal.
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212
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Caffeine acts through neuronal adenosine A2A receptors to prevent mood and memory dysfunction triggered by chronic stress. Proc Natl Acad Sci U S A 2015; 112:7833-8. [PMID: 26056314 DOI: 10.1073/pnas.1423088112] [Citation(s) in RCA: 236] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The consumption of caffeine (an adenosine receptor antagonist) correlates inversely with depression and memory deterioration, and adenosine A2A receptor (A2AR) antagonists emerge as candidate therapeutic targets because they control aberrant synaptic plasticity and afford neuroprotection. Therefore we tested the ability of A2AR to control the behavioral, electrophysiological, and neurochemical modifications caused by chronic unpredictable stress (CUS), which alters hippocampal circuits, dampens mood and memory performance, and enhances susceptibility to depression. CUS for 3 wk in adult mice induced anxiogenic and helpless-like behavior and decreased memory performance. These behavioral changes were accompanied by synaptic alterations, typified by a decrease in synaptic plasticity and a reduced density of synaptic proteins (synaptosomal-associated protein 25, syntaxin, and vesicular glutamate transporter type 1), together with an increased density of A2AR in glutamatergic terminals in the hippocampus. Except for anxiety, for which results were mixed, CUS-induced behavioral and synaptic alterations were prevented by (i) caffeine (1 g/L in the drinking water, starting 3 wk before and continued throughout CUS); (ii) the selective A2AR antagonist KW6002 (3 mg/kg, p.o.); (iii) global A2AR deletion; and (iv) selective A2AR deletion in forebrain neurons. Notably, A2AR blockade was not only prophylactic but also therapeutically efficacious, because a 3-wk treatment with the A2AR antagonist SCH58261 (0.1 mg/kg, i.p.) reversed the mood and synaptic dysfunction caused by CUS. These results herald a key role for synaptic A2AR in the control of chronic stress-induced modifications and suggest A2AR as candidate targets to alleviate the consequences of chronic stress on brain function.
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213
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Diamond ML, Ritter AC, Jackson EK, Conley YP, Kochanek PM, Boison D, Wagner AK. Genetic variation in the adenosine regulatory cycle is associated with posttraumatic epilepsy development. Epilepsia 2015; 56:1198-206. [PMID: 26040919 DOI: 10.1111/epi.13044] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/29/2015] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Determine if genetic variation in enzymes/transporters influencing extracellular adenosine homeostasis, including adenosine kinase (ADK), [ecto-5'-nucleotidase (NT5E), cluster of differentiation 73 (CD73)], and equilibrative nucleoside transporter type-1 (ENT-1), is significantly associated with epileptogenesis and posttraumatic epilepsy (PTE) risk, as indicated by time to first seizure analyses. METHODS Nine ADK, three CD73, and two ENT-1 tagging single nucleotide polymorphisms (SNPs) were genotyped in 162 white adults with moderate/severe traumatic brain injury (TBI) and no history of premorbid seizures. Kaplan-Meier models were used to screen for genetic differences in time to first seizure occurring >1 week post-TBI. SNPs remaining significant after correction for multiple comparisons were examined using Cox proportional hazards analyses, adjusting for subdural hematoma, injury severity score, and isolated TBI status. SNPs significant in multivariate models were then entered simultaneously into an adjusted Cox model. RESULTS Comparing Kaplan-Meier curves, rs11001109 (ADK) rare allele homozygosity and rs9444348 (NT5E) heterozygosity were significantly associated with shorter time to first seizure and an increased seizure rate 3 years post-TBI. Multivariate Cox proportional hazard models showed that these genotypes remained significantly associated with increased PTE hazard up to 3 years post-TBI after controlling for variables of interest (rs11001109: hazard ratio (HR) 4.47, 95% confidence interval (CI) 1.27-15.77, p = 0.020; rs9444348: HR 2.95, 95% CI 1.19-7.31, p = 0.019) . SIGNIFICANCE Genetic variation in ADK and NT5E may help explain variability in time to first seizure and PTE risk, independent of previously identified risk factors, after TBI. Once validated, identifying genetic variation in adenosine regulatory pathways relating to epileptogenesis and PTE may facilitate exploration of therapeutic targets and pharmacotherapy development.
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Affiliation(s)
- Matthew L Diamond
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, U.S.A
| | - Anne C Ritter
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, U.S.A
| | - Edwin K Jackson
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, U.S.A
| | - Yvette P Conley
- Department of Health Promotion and Human Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, U.S.A.,Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania, U.S.A
| | - Patrick M Kochanek
- Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, U.S.A.,Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania, U.S.A
| | - Detlev Boison
- RS Dow Neurobiology Labs, Legacy Research Institute, Portland, Oregon, U.S.A
| | - Amy K Wagner
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, U.S.A.,Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania, U.S.A.,Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania, U.S.A
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214
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Chronic Cerebral Ischemia Induces Downregulation of A1 Adenosine Receptors During White Matter Damage in Adult Mice. Cell Mol Neurobiol 2015; 35:1149-56. [DOI: 10.1007/s10571-015-0208-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 05/06/2015] [Indexed: 12/20/2022]
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215
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León-Navarro DA, Albasanz JL, Martín M. Hyperthermia-induced seizures alter adenosine A1
and A2A
receptors and 5′-nucleotidase activity in rat cerebral cortex. J Neurochem 2015; 134:395-404. [DOI: 10.1111/jnc.13130] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 03/27/2015] [Accepted: 03/30/2015] [Indexed: 12/20/2022]
Affiliation(s)
- David Agustín León-Navarro
- Departamento de Química Inorgánica; Orgánica y Bioquímica; Facultad de Ciencias y Tecnologías Químicas; Centro Regional de Investigaciones Biomédicas; Universidad de Castilla-La Mancha; Avenida Camilo José Cela; Ciudad Real Spain
| | - José L. Albasanz
- Departamento de Química Inorgánica; Orgánica y Bioquímica; Facultad de Ciencias y Tecnologías Químicas; Centro Regional de Investigaciones Biomédicas; Universidad de Castilla-La Mancha; Avenida Camilo José Cela; Ciudad Real Spain
| | - Mairena Martín
- Departamento de Química Inorgánica; Orgánica y Bioquímica; Facultad de Ciencias y Tecnologías Químicas; Centro Regional de Investigaciones Biomédicas; Universidad de Castilla-La Mancha; Avenida Camilo José Cela; Ciudad Real Spain
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216
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Chen JF, Lee CF, Chern Y. Adenosine receptor neurobiology: overview. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2015; 119:1-49. [PMID: 25175959 DOI: 10.1016/b978-0-12-801022-8.00001-5] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Adenosine is a naturally occurring nucleoside that is distributed ubiquitously throughout the body as a metabolic intermediary. In the brain, adenosine functions as an important upstream neuromodulator of a broad spectrum of neurotransmitters, receptors, and signaling pathways. By acting through four G-protein-coupled receptors, adenosine contributes critically to homeostasis and neuromodulatory control of a variety of normal and abnormal brain functions, ranging from synaptic plasticity, to cognition, to sleep, to motor activity to neuroinflammation, and cell death. This review begun with an overview of the gene and genome structure and the expression pattern of adenosine receptors (ARs). We feature several new developments over the past decade in our understanding of AR functions in the brain, with special focus on the identification and characterization of canonical and noncanonical signaling pathways of ARs. We provide an update on functional insights from complementary genetic-knockout and pharmacological studies on the AR control of various brain functions. We also highlight several novel and recent developments of AR neurobiology, including (i) recent breakthrough in high resolution of three-dimension structure of adenosine A2A receptors (A2ARs) in several functional status, (ii) receptor-receptor heterodimerization, (iii) AR function in glial cells, and (iv) the druggability of AR. We concluded the review with the contention that these new developments extend and strengthen the support for A1 and A2ARs in brain as therapeutic targets for neurologic and psychiatric diseases.
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Affiliation(s)
- Jiang-Fan Chen
- Department of Neurology, Boston University School of Medicine, Boston, Massachusetts, USA.
| | - Chien-fei Lee
- Division of Neuroscience, Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yijuang Chern
- Division of Neuroscience, Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
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217
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Rodrigues RJ, Tomé AR, Cunha RA. ATP as a multi-target danger signal in the brain. Front Neurosci 2015; 9:148. [PMID: 25972780 PMCID: PMC4412015 DOI: 10.3389/fnins.2015.00148] [Citation(s) in RCA: 190] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 04/10/2015] [Indexed: 12/13/2022] Open
Abstract
ATP is released in an activity-dependent manner from different cell types in the brain, fulfilling different roles as a neurotransmitter, neuromodulator, in astrocyte-to-neuron communication, propagating astrocytic responses and formatting microglia responses. This involves the activation of different ATP P2 receptors (P2R) as well as adenosine receptors upon extracellular ATP catabolism by ecto-nucleotidases. Notably, brain noxious stimuli trigger a sustained increase of extracellular ATP, which plays a key role as danger signal in the brain. This involves a combined action of extracellular ATP in different cell types, namely increasing the susceptibility of neurons to damage, promoting astrogliosis and recruiting and formatting microglia to mount neuroinflammatory responses. Such actions involve the activation of different receptors, as heralded by neuroprotective effects resulting from blockade mainly of P2X7R, P2Y1R and adenosine A2A receptors (A2AR), which hierarchy, cooperation and/or redundancy is still not resolved. These pleiotropic functions of ATP as a danger signal in brain damage prompt a therapeutic interest to multi-target different purinergic receptors to provide maximal opportunities for neuroprotection.
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Affiliation(s)
- Ricardo J Rodrigues
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra Coimbra, Portugal ; Institute for Interdisciplinary Research, University of Coimbra Coimbra, Portugal
| | - Angelo 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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218
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George J, Gonçalves FQ, Cristóvão G, Rodrigues L, Meyer Fernandes JR, Gonçalves T, Cunha RA, Gomes CA. Different danger signals differently impact on microglial proliferation through alterations of ATP release and extracellular metabolism. Glia 2015; 63:1636-45. [PMID: 25847308 DOI: 10.1002/glia.22833] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 03/17/2015] [Indexed: 12/20/2022]
Abstract
Microglia rely on their ability to proliferate in the brain parenchyma to sustain brain innate immunity and participate in the reaction to brain damage. We now studied the influence of different danger signals activating microglia, both internal (typified by glutamate, associated with brain damage) and external (using a bacterial lipopolysaccharide, LPS), on the proliferation of microglia cells. We found that LPS (100 ng/mL) increased, whereas glutamate (0.5 mM) decreased proliferation. Notably, LPS decreased whereas glutamate increased the extracellular levels of ATP. In contrast, LPS increased whereas glutamate decreased the extracellular catabolism of ATP into adenosine through ecto-nucleotidases and ecto-5'-nucleotidase. Finally, apyrase (degrades extracellular ATP) abrogated glutamate-induced inhibition of microglia proliferation; conversely, inhibitors of ecto-nucleotidases (ARL67156 or α,β-methylene ADP) and adenosine deaminase (degrades extracellular adenosine) abrogated the LPS-induced increase of microglia proliferation, which was blocked by a selective A2A receptor antagonist, SCH58261 (50 nM). Overall, these results highlight the importance of the extracellular purinergic metabolism to format microglia proliferation and influence the spatio-temporal profile of neuroinflammation in different conditions of brain damage.
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Affiliation(s)
- Jimmy George
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Portugal
| | | | - Gonçalo Cristóvão
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Portugal
| | - Lisa Rodrigues
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Portugal.,FMUC-Faculty of Medicine, University of Coimbra, Portugal
| | | | - Teresa Gonçalves
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Portugal.,FMUC-Faculty of Medicine, University of Coimbra, Portugal
| | - Rodrigo A Cunha
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Portugal.,FMUC-Faculty of Medicine, University of Coimbra, Portugal
| | - Catarina A Gomes
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Portugal.,FMUC-Faculty of Medicine, University of Coimbra, Portugal
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219
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Constantino LC, Pamplona FA, Matheus FC, Ludka FK, Gomez-Soler M, Ciruela F, Boeck CR, Prediger RD, Tasca CI. Adenosine A1 receptor activation modulates N-methyl-d-aspartate (NMDA) preconditioning phenotype in the brain. Behav Brain Res 2015; 282:103-10. [DOI: 10.1016/j.bbr.2014.12.056] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 12/22/2014] [Accepted: 12/25/2014] [Indexed: 12/20/2022]
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220
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Neuroinflammation after neonatal hypoxia–ischemia is associated with alterations in the purinergic system: adenosine deaminase 1 isoenzyme is the most predominant after insult. Mol Cell Biochem 2015; 403:169-77. [DOI: 10.1007/s11010-015-2347-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 01/30/2015] [Indexed: 12/19/2022]
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221
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Zhang P, Bannon NM, Ilin V, Volgushev M, Chistiakova M. Adenosine effects on inhibitory synaptic transmission and excitation-inhibition balance in the rat neocortex. J Physiol 2015; 593:825-41. [PMID: 25565160 DOI: 10.1113/jphysiol.2014.279901] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 11/28/2014] [Indexed: 12/20/2022] Open
Abstract
KEY POINTS Adenosine might be the most widespread neuromodulator in the brain, but its effects on inhibitory transmission in the neocortex are not understood. Here we report that adenosine suppresses inhibitory transmission to layer 2/3 pyramidal neurons via activation of presynaptic A1 receptors. We present evidence for functional A2A receptors, which have a weak modulatory effect on the A1-mediated suppression, at about 50% of inhibitory synapses at pyramidal neurons. Adenosine suppresses excitatory and inhibitory transmission to a different extent, and can change the excitation-inhibition balance at a set of synapses bidirectionally, but on average the balance was maintained during application of adenosine. These results suggest that changes of adenosine concentration may lead to differential modulation of excitatory-inhibitory balance in pyramidal neurons, and thus redistribution of local spotlights of activity in neocortical circuits, while preserving the balanced state of the whole network. ABSTRACT Adenosine might be the most widespread neuromodulator in the brain: as a metabolite of ATP it is present in every neuron and glial cell. However, how adenosine affects operation of neurons and networks in the neocortex is poorly understood, mostly because modulation of inhibitory transmission by adenosine has been so little studied. To clarify adenosine's role at inhibitory synapses, and in excitation-inhibition balance in pyramidal neurons, we recorded pharmacologically isolated inhibitory responses, compound excitatory-inhibitory responses and spontaneous events in layer 2/3 pyramidal neurons in slices from rat visual cortex. We show that adenosine (1-150 μm) suppresses inhibitory transmission to these neurons in a concentration-dependent and reversible manner. The suppression was mediated by presynaptic A1 receptors (A1Rs) because it was blocked by a selective A1 antagonist, DPCPX, and associated with changes of release indices: paired-pulse ratio, inverse coefficient of variation and frequency of miniature events. At some synapses (12 out of 24) we found evidence for A2ARs: their blockade led to a small but significant increase of the magnitude of adenosine-mediated suppression. This effect of A2AR blockade was not observed when A1Rs were blocked, suggesting that A2ARs do not have their own effect on transmission, but can modulate the A1R-mediated suppression. At both excitatory and inhibitory synapses, the magnitude of A1R-mediated suppression and A2AR-A1R interaction expressed high variability, suggesting high heterogeneity of synapses in the sensitivity to adenosine. Adenosine could change the balance between excitation and inhibition at a set of inputs to a neuron bidirectionally, towards excitation or towards inhibition. On average, however, these bidirectional changes cancelled each other, and the overall balance of excitation and inhibition was maintained during application of adenosine. These results suggest that changes of adenosine concentration may lead to differential modulation of excitatory-inhibitory balance in pyramidal neurons, and thus redistribution of local spotlights of activity in neocortical circuits, while preserving the balanced state of the whole network.
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Affiliation(s)
- Pei Zhang
- Department of Psychology, University of Connecticut, Storrs, CT, 06269, USA
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222
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Purine receptors are required for DHA-mediated neuroprotection against oxygen and glucose deprivation in hippocampal slices. Purinergic Signal 2014; 11:117-26. [PMID: 25504554 DOI: 10.1007/s11302-014-9438-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 12/04/2014] [Indexed: 12/20/2022] Open
Abstract
Docosahexaenoic acid (DHA) is important for central nervous system function during pathological states such as ischemia. DHA reduces neuronal injury in experimental brain ischemia; however, the underlying mechanisms are not well understood. In the present study, we investigated the effects of DHA on acute hippocampal slices subjected to experimental ischemia by transient oxygen and glucose deprivation (OGD) and re-oxygenation and the possible involvement of purinergic receptors as the mechanism underlying DHA-mediated neuroprotection. We observed that cellular viability reduction induced by experimental ischemia as well as cell damage and thiobarbituric acid reactive substances (TBARS) production induced by glutamate (10 mM) were prevented by hippocampal slices pretreated with DHA (5 μM). However, glutamate uptake reduction induced by OGD and re-oxygenation was not prevented by DHA. The beneficial effect of DHA against cellular viability reduction induced by OGD and re-oxygenation was blocked with PPADS (3 μM), a nonselective P2X1-5 receptor antagonist as well as with a combination of TNP-APT (100 nM) plus brilliant blue (100 nM), which blocked P2X1, P2X3, P2X2/3, and P2X7 receptors, respectively. Moreover, adenosine receptors blockade with A1 receptor antagonist DPCPX (100 nM) or with A2B receptor antagonist alloxazine (100 nM) inhibited DHA-mediated neuroprotection. The addition of an A2A receptor antagonist ZM241385 (50 nM), or A3 receptor antagonist VUF5574 (1 μM) was ineffective. Taken together, our results indicated that neuroprotective actions of DHA may depend on P2X, A1, and A2B purinergic receptors activation. Our results reinforce the notion that dietary DHA may act as a local purinergic modulator in order to prevent neurodegenerative diseases.
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223
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Nunes AR, Alves MG, Moreira PI, Oliveira PF, Silva BM. Can Tea Consumption be a Safe and Effective Therapy Against Diabetes Mellitus-Induced Neurodegeneration? Curr Neuropharmacol 2014; 12:475-89. [PMID: 25977676 PMCID: PMC4428023 DOI: 10.2174/1570159x13666141204220539] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 10/10/2014] [Accepted: 12/03/2014] [Indexed: 12/20/2022] Open
Abstract
Diabetes mellitus (DM) is a metabolic disease that is rapidly increasing and has become a major public health problem. Type 2 DM (T2DM) is the most common type, accounting for up to 90-95% of the new diagnosed DM cases. The brain is very susceptible to glucose fluctuations and hyperglycemia-induced oxidative stress (OS). It is well known that DM and the risk of developing neurodegenerative diseases are associated. Tea, Camellia sinensis L., is one of the most consumed beverages. It contains several phytochemicals, such as polyphenols, methylxanthines (mainly caffeine) and L-theanine that are often reported to be responsible for tea's health benefits, including in brain. Tea phytochemicals have been reported to be responsible for tea's significant antidiabetic and neuroprotective properties and antioxidant potential. Epidemiological studies have shown that regular consumption of tea has positive effects on DM-caused complications and protects the brain against oxidative damage, contributing to an improvement of the cognitive function. Among the several reported benefits of tea consumption, those related with neurodegenerative diseases are of great interest. Herein, we discuss the potential beneficial effects of tea consumption and tea phytochemicals on DM and how their action can counteract the severe brain damage induced by this disease.
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Affiliation(s)
- Ana R. Nunes
- CICS – UBI – Health Sciences Research Centre, University of Beira Interior, 6201-506 Covilhã, Portugal
| | - Marco G. Alves
- CICS – UBI – Health Sciences Research Centre, University of Beira Interior, 6201-506 Covilhã, Portugal
| | - Paula I. Moreira
- CNC – Center for Neuroscience and Cell Biology, University of Coimbra and Laboratory of Physiology, Faculty of Medicine, University of Coimbra, 3004-517 Coimbra, Portugal
| | - Pedro F. Oliveira
- CICS – UBI – Health Sciences Research Centre, University of Beira Interior, 6201-506 Covilhã, Portugal
| | - Branca M. Silva
- CICS – UBI – Health Sciences Research Centre, University of Beira Interior, 6201-506 Covilhã, Portugal
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224
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Chiu GS, Freund GG. Modulation of neuroimmunity by adenosine and its receptors: metabolism to mental illness. Metabolism 2014; 63:1491-8. [PMID: 25308443 PMCID: PMC4252699 DOI: 10.1016/j.metabol.2014.09.003] [Citation(s) in RCA: 23] [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: 05/18/2014] [Revised: 08/14/2014] [Accepted: 09/19/2014] [Indexed: 12/20/2022]
Abstract
Adenosine is a pleiotropic bioactive with potent neuromodulatory properties. Due to its ability to easily cross the blood-brain barrier, it can act as a signaling molecule between the periphery and the brain. It functions through four (A1, A2A, A2B, and A3) cell surface G protein-coupled adenosine receptors (ARs) that are expressed in some combination on nearly all cells types within the CNS. By regulating the activity of adenylyl cyclase and changing the intracellular concentration of cAMP, adenosine can alter neuronal function and neurotransmission. A variety of illnesses related to metabolic dysregulation, such as type 1 diabetes and Alzheimer's disease, are associated with an elevated serum concentration of adenosine and a pathogenesis rooted in inflammation. This review describes the accepted physiologic function of adenosine in neurological disease and explores its new potential as a peripheral to central danger signal that can activate the neuroimmune system and contribute to symptoms of sickness and psychopathologies.
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Affiliation(s)
- Gabriel S Chiu
- Division of Nutritional Sciences, University of Illinois, Urbana IL, USA; Department of Pathology, Program in Integrative Immunology and Behavior, University of Illinois, Urbana IL, USA
| | - Gregory G Freund
- Division of Nutritional Sciences, University of Illinois, Urbana IL, USA; Department of Pathology, Program in Integrative Immunology and Behavior, University of Illinois, Urbana IL, USA; Department of Animal Sciences, University of Illinois, Urbana IL, USA.
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225
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Methionine Exposure Alters Glutamate Uptake and Adenine Nucleotide Hydrolysis in the Zebrafish Brain. Mol Neurobiol 2014; 53:200-209. [PMID: 25421208 DOI: 10.1007/s12035-014-8983-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 11/03/2014] [Indexed: 12/20/2022]
Abstract
Hypermethioninemic patients may exhibit different neurological dysfunctions, and the mechanisms underlying these pathologies remain obscure. Glutamate and ATP are important excitatory neurotransmitters co-released at synaptic clefts, and whose activities are intrinsically related. Adenosine-the final product of ATP breakdown-is also an important neuromodulator. Here, we investigated the effects of long-term (7-day) exposure to 1.5 or 3 mM methionine (Met) on glutamate uptake in brain tissues (telencephalon, optic tectum, and cerebellum) and on ATP, ADP, and AMP catabolism by ecto-nucleotidases found in brain membrane samples, using a zebrafish model. Also, we evaluated the expression of ecto-nucleotidase (ntdp1, ntdp2mg, ntdp2mq, ntdp2mv, ntdp3, and nt5e) and adenosine receptor (adora1, adora2aa, adora2ab, adora2b) genes in the brain of zebrafish exposed to Met. In animals exposed to 3.0 mM Met, glutamate uptake in the telencephalon decreased significantly. Also, ATP and ADP (but not AMP) catabolism decreased significantly at both Met concentrations tested. The messenger RNA (mRNA) levels of ntpd genes and of the adenosine receptors adora1 and adora2aa increased significantly after Met exposure. In contrast, adora2ab mRNA levels decreased after Met exposure. Our data suggest that glutamate and ATP accumulate at synaptic clefts after Met exposure, with potential detrimental effects to the nervous system. This phenomenon might explain, at least in part, the increased susceptibility of hypermethioninemic patients to neurological symptoms.
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226
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Upregulation of nucleoside triphosphate diphosphohydrolase-1 and ecto-5'-nucleotidase in rat hippocampus after repeated low-dose dexamethasone administration. J Mol Neurosci 2014; 55:959-67. [PMID: 25367797 DOI: 10.1007/s12031-014-0452-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 10/17/2014] [Indexed: 12/20/2022]
Abstract
Although dexamethasone (DEX), a synthetic glucocorticoid receptor (GR) analog with profound effects on energy metabolism, immune system, and hypothalamic-pituitary-adrenal axis, is widely used therapeutically, its impact on the brain is poorly understood. The aim of the present study was to explore the effect of repeated low-dose DEX administration on the activity and expression of the ectonucleotidase enzymes which hydrolyze and therefore control extracellular ATP and adenosine concentrations in the synaptic cleft. Ectonucleotidases tested were ectonucleoside triphosphate diphosphohydrolase 1-3 (NTPDase1-3) and ecto-5'-nucleotidase (eN), whereas the effects were evaluated in two brain areas that show different sensitivity to glucocorticoid action, hippocampus, and cerebral cortex. In the hippocampus, but not in cerebral cortex, modest level of neurodegenerative changes as well as increase in ATP, ADP, and AMP hydrolysis and upregulation of NTPDase1 and eN mRNA expression ensued under the influence of DEX. The observed pattern of ectonucleotidase activation, which creates tissue volume with enhanced capacity for adenosine formation, is the hallmark of the response after different insults to the brain.
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227
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Natural products from marine organisms with neuroprotective activity in the experimental models of Alzheimer's disease, Parkinson's disease and ischemic brain stroke: their molecular targets and action mechanisms. Arch Pharm Res 2014; 38:139-70. [PMID: 25348867 DOI: 10.1007/s12272-014-0503-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 10/14/2014] [Indexed: 12/20/2022]
Abstract
Continuous increases in the incidence of neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), and brain stroke demand the urgent development of therapeutics. Marine organisms are well-known producers of natural products with diverse structures and pharmacological activities. Therefore, researchers have endeavored to identify marine natural products with neuroprotective effects. In this regard, this review summarizes therapeutic targets for AD, PD, and ischemic brain stroke and marine natural products with pharmacological activities on the targets according to taxonomies of marine organisms. Furthermore, several marine natural products on the clinical trials for the treatment of neurological disorders are discussed.
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228
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Miranda MF, Hamani C, de Almeida ACG, Amorim BO, Macedo CE, Fernandes MJS, Nobrega JN, Aarão MC, Madureira AP, Rodrigues AM, Andersen ML, Tufik S, Mello LE, Covolan L. Role of adenosine in the antiepileptic effects of deep brain stimulation. Front Cell Neurosci 2014; 8:312. [PMID: 25324724 PMCID: PMC4183090 DOI: 10.3389/fncel.2014.00312] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Accepted: 09/17/2014] [Indexed: 12/20/2022] Open
Abstract
Despite the effectiveness of anterior thalamic nucleus (AN) deep brain stimulation (DBS) for the treatment of epilepsy, mechanisms responsible for the antiepileptic effects of this therapy remain elusive. As adenosine modulates neuronal excitability and seizure activity in animal models, we hypothesized that this nucleoside could be one of the substrates involved in the effects of AN DBS. We applied 5 days of stimulation to rats rendered chronically epileptic by pilocarpine injections and recorded epileptiform activity in hippocampal slices. We found that slices from animals given DBS had reduced hippocampal excitability and were less susceptible to develop ictal activity. In live animals, AN DBS significantly increased adenosine levels in the hippocampus as measured by microdialysis. The reduced excitability of DBS in vitro was completely abolished in animals pre-treated with A1 receptor antagonists and was strongly potentiated by A1 receptor agonists. We conclude that some of the antiepileptic effects of DBS may be mediated by adenosine.
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Affiliation(s)
- Maisa F Miranda
- Laboratório de Neurociência Experimental e Computacional, Universidade Federal de São João del-Rei São João del-Rei, Brazil
| | - Clement Hamani
- Disciplina de Neurofisiologia, Universidade Federal de São Paulo São Paulo, Brazil ; Behavioural Neurobiology Laboratory, Centre for Addiction and Mental Health Toronto, Canada ; Division of Neurosurgery, Toronto Western Hospital, University of Toronto Toronto, Canada
| | - Antônio-Carlos G de Almeida
- Laboratório de Neurociência Experimental e Computacional, Universidade Federal de São João del-Rei São João del-Rei, Brazil
| | - Beatriz O Amorim
- Disciplina de Neurofisiologia, Universidade Federal de São Paulo São Paulo, Brazil
| | - Carlos E Macedo
- Departamento de Psicobiologia, Universidade Federal de São Paulo São Paulo, Brazil
| | - Maria José S Fernandes
- Disciplina de Neurologia Experimental, Universidade Federal de São Paulo São Paulo, Brazil
| | - José N Nobrega
- Behavioural Neurobiology Laboratory, Centre for Addiction and Mental Health Toronto, Canada
| | - Mayra C Aarão
- Laboratório de Neurociência Experimental e Computacional, Universidade Federal de São João del-Rei São João del-Rei, Brazil
| | - Ana Paula Madureira
- Laboratório de Neurociência Experimental e Computacional, Universidade Federal de São João del-Rei São João del-Rei, Brazil
| | - Antônio M Rodrigues
- Laboratório de Neurociência Experimental e Computacional, Universidade Federal de São João del-Rei São João del-Rei, Brazil
| | - Monica L Andersen
- Departamento de Psicobiologia, Universidade Federal de São Paulo São Paulo, Brazil
| | - Sergio Tufik
- Departamento de Psicobiologia, Universidade Federal de São Paulo São Paulo, Brazil
| | - Luiz E Mello
- Disciplina de Neurofisiologia, Universidade Federal de São Paulo São Paulo, Brazil
| | - Luciene Covolan
- Disciplina de Neurofisiologia, Universidade Federal de São Paulo São Paulo, Brazil
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229
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Mallok A, Vaillant JD, Soto MTD, Viebahn-Hänsler R, Viart MDLAB, Pérez AF, Cedeño RID, Fernández OSL. Ozone protective effects against PTZ-induced generalized seizures are mediated by reestablishment of cellular redox balance and A1adenosine receptors. Neurol Res 2014; 37:204-10. [DOI: 10.1179/1743132814y.0000000445] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Prolonged adenosine A1 receptor activation in hypoxia and pial vessel disruption focal cortical ischemia facilitates clathrin-mediated AMPA receptor endocytosis and long-lasting synaptic inhibition in rat hippocampal CA3-CA1 synapses: differential regulation of GluA2 and GluA1 subunits by p38 MAPK and JNK. J Neurosci 2014; 34:9621-43. [PMID: 25031403 DOI: 10.1523/jneurosci.3991-13.2014] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Activation of presynaptic adenosine A1 receptors (A1Rs) causes substantial synaptic depression during hypoxia/cerebral ischemia, but postsynaptic actions of A1Rs are less clear. We found that A1Rs and GluA2-containing AMPA receptors (AMPARs) form stable protein complexes from hippocampal brain homogenates and cultured hippocampal neurons from Sprague Dawley rats. In contrast, adenosine A2A receptors (A2ARs) did not coprecipitate or colocalize with GluA2-containing AMPARs. Prolonged stimulation of A1Rs with the agonist N(6)-cyclopentyladenosine (CPA) caused adenosine-induced persistent synaptic depression (APSD) in hippocampal brain slices, and APSD levels were blunted by inhibiting clathrin-mediated endocytosis of GluA2 subunits with the Tat-GluA2-3Y peptide. Using biotinylation and membrane fractionation assays, prolonged CPA incubation showed significant depletion of GluA2/GluA1 surface expression from hippocampal brain slices and cultured neurons. Tat-GluA2-3Y peptide or dynamin inhibitor Dynasore prevented CPA-induced GluA2/GluA1 internalization. Confocal imaging analysis confirmed that functional A1Rs, but not A2ARs, are required for clathrin-mediated AMPAR endocytosis in hippocampal neurons. Pharmacological inhibitors or shRNA knockdown of p38 MAPK and JNK prevented A1R-mediated internalization of GluA2 but not GluA1 subunits. Tat-GluA2-3Y peptide or A1R antagonist 8-cyclopentyl-1,3-dipropylxanthine also prevented hypoxia-mediated GluA2/GluA1 internalization. Finally, in a pial vessel disruption cortical stroke model, a unilateral cortical lesion compared with sham surgery reduced hippocampal GluA2, GluA1, and A1R surface expression and also caused synaptic depression in hippocampal slices that was consistent with AMPAR downregulation and decreased probability of transmitter release. Together, these results indicate a previously unknown mechanism for A1R-induced persistent synaptic depression involving clathrin-mediated GluA2 and GluA1 internalization that leads to hippocampal neurodegeneration after hypoxia/cerebral ischemia.
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Adenosine amine congener as a cochlear rescue agent. BIOMED RESEARCH INTERNATIONAL 2014; 2014:841489. [PMID: 25243188 PMCID: PMC4160640 DOI: 10.1155/2014/841489] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 07/29/2014] [Indexed: 12/20/2022]
Abstract
We have previously shown that adenosine amine congener (ADAC), a selective A1 adenosine receptor agonist, can ameliorate noise- and cisplatin-induced cochlear injury. Here we demonstrate the dose-dependent rescue effects of ADAC on noise-induced cochlear injury in a rat model and establish the time window for treatment. Methods. ADAC (25–300 μg/kg) was administered intraperitoneally to Wistar rats (8–10 weeks old) at intervals (6–72 hours) after exposure to traumatic noise (8–16 kHz, 110 dB sound pressure level, 2 hours). Hearing sensitivity was assessed using auditory brainstem responses (ABR) before and 12 days after noise exposure. Pharmacokinetic studies investigated ADAC concentrations in plasma after systemic (intravenous) administration. Results. ADAC was most effective in the first 24 hours after noise exposure at doses >50 μg/kg, providing up to 21 dB protection (averaged across 8–28 kHz). Pharmacokinetic studies demonstrated a short (5 min) half-life of ADAC in plasma after intravenous administration without detection of degradation products. Conclusion. Our data show that ADAC mitigates noise-induced hearing loss in a dose- and time-dependent manner, but further studies are required to establish its translation as a clinical otological treatment.
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Ferrante A, Martire A, Pepponi R, Varani K, Vincenzi F, Ferraro L, Beggiato S, Tebano MT, Popoli P. Expression, pharmacology and functional activity of adenosine A1 receptors in genetic models of Huntington's disease. Neurobiol Dis 2014; 71:193-204. [PMID: 25132555 DOI: 10.1016/j.nbd.2014.08.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 07/15/2014] [Accepted: 08/06/2014] [Indexed: 12/20/2022] Open
Abstract
Adenosine A1 receptor (A1R) stimulation exerts beneficial effects in response to various insults to the brain and, although it was found neuroprotective in a lesional model of Huntington's disease (HD), the features of this receptor in genetic models of HD have never been explored. In the present study we characterized the expression, affinity and functional effects of A1Rs in R6/2 mice (the most widely used transgenic model of HD) and in a cellular model of HD. Binding studies revealed that the density of A1Rs was significantly reduced in the cortex and the striatum of R6/2 mice compared to age-matched wild-type (WT), while receptor affinity was unchanged. The selective A1R agonist cyclopentyladenosine (CPA, 300nM) was significantly more effective in reducing synaptic transmission in corticostriatal slices from symptomatic R6/2 than in age-matched WT mice. Such an effect was due to a stronger inhibition of glutamate release from the pre-synaptic terminal. The different functional activities of A1Rs in HD mice were associated also to a different intracellular signaling pathway involved in the synaptic effect of CPA. In fact, while the PKA pathway was involved in both genotypes, p38 MAPK inhibitor SB203580 partially prevented synaptic effects of CPA in R6/2, but not in WT, mice; moreover, CPA differently modulated the phosphorylation status of p38 in the two genotypes. In vitro studies confirmed a different behavior of A1Rs in HD: CPA (100 nM for 5h) modulated cell viability in STHdh(Q111/Q111) (mhttHD cells), without affecting the viability of STHdh(Q7/Q7) (wthtt cells). This effect was prevented by the application of SB203580. Our results demonstrate that in the presence of the HD mutation A1Rs undergo profound changes in terms of expression, pharmacology and functional activity. These changes have to be taken in due account when considering A1Rs as a potential therapeutic target for this disease.
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Affiliation(s)
- Antonella Ferrante
- Istituto Superiore di Sanità, Department of Therapeutic Research and Medicines Evaluation, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Alberto Martire
- Istituto Superiore di Sanità, Department of Therapeutic Research and Medicines Evaluation, Viale Regina Elena 299, 00161 Rome, Italy
| | - Rita Pepponi
- Istituto Superiore di Sanità, Department of Therapeutic Research and Medicines Evaluation, Viale Regina Elena 299, 00161 Rome, Italy
| | - Katia Varani
- Department of Medical Sciences, Pharmacology Section, University of Ferrara, via Fossato di Mortara 17/19, 44121 Ferrara, Italy
| | - Fabrizio Vincenzi
- Department of Medical Sciences, Pharmacology Section, University of Ferrara, via Fossato di Mortara 17/19, 44121 Ferrara, Italy
| | - Luca Ferraro
- Department of Life Sciences and Biotechnology, University of Ferrara, Via Fossato di Mortara 17, 44121 Ferrara, Italy
| | - Sarah Beggiato
- Department of Medical Sciences, Pharmacology Section, University of Ferrara, via Fossato di Mortara 17/19, 44121 Ferrara, Italy
| | - Maria Teresa Tebano
- Istituto Superiore di Sanità, Department of Therapeutic Research and Medicines Evaluation, Viale Regina Elena 299, 00161 Rome, Italy
| | - Patrizia Popoli
- Istituto Superiore di Sanità, Department of Therapeutic Research and Medicines Evaluation, Viale Regina Elena 299, 00161 Rome, Italy
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Antonioli L, Csóka B, Fornai M, Colucci R, Kókai E, Blandizzi C, Haskó G. Adenosine and inflammation: what's new on the horizon? Drug Discov Today 2014; 19:1051-68. [DOI: 10.1016/j.drudis.2014.02.010] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 02/06/2014] [Accepted: 02/25/2014] [Indexed: 12/18/2022]
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Giunta S, Andriolo V, Castorina A. Dual blockade of the A1 and A2A adenosine receptor prevents amyloid beta toxicity in neuroblastoma cells exposed to aluminum chloride. Int J Biochem Cell Biol 2014; 54:122-36. [PMID: 25058312 DOI: 10.1016/j.biocel.2014.07.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 06/25/2014] [Accepted: 07/11/2014] [Indexed: 02/06/2023]
Abstract
In a previous work we have shown that exposure to aluminum (Al) chloride (AlCl3) enhanced the neurotoxicity of the amyloid beta(25-35) fragment (Abeta(25-35)) in neuroblastoma cells and affected the expression of Alzheimer's disease (AD)-related genes. Caffein, a compound endowed with beneficial effects against AD, exerts neuroprotection primarily through its antagonist activity on A2A adenosine receptors (A2AR), although it also inhibits A1Rs with similar potency. Still, studies on the specific involvement of these receptors in neuroprotection in a model of combined neurotoxicity (Abeta(25-35)+AlCl3) are missing. To address this issue, cultured SH-SY5Y cells exposed to Abeta(25-35)+AlCl3 were assessed for cell viability, morphology, intracellular ROS activity and expression of apoptosis-, stress- and AD-related proteins. To define the role of A1R and A2ARs, pretreatment with caffein, specific receptor antagonists (DPCPX or SCH58261) or siRNA-mediated gene knockdown were delivered. Results indicate that AlCl3 treatment exacerbated Abeta(25-35) toxicity, increased ROS production, lipid peroxidation, β-secretase-1 (BACE1) and amyloid precursor protein (APP). Interestingly, SCH58261 successfully prevented toxicity associated to Abeta(25-35) only, whereas pretreatment with both DPCPX and SCH58261 was required to fully avert Abeta(25-35)+AlCl3-induced damage, suggesting that A1Rs might also be critically involved in protection during combined toxicity. The effects of caffein were mimicked by both N-acetyl cysteine, an antioxidant, and desferrioxamine, likely acting through distinct mechanisms. Altogether, our data establish a novel protective function associated with A1R inhibition in the setting of combined Abeta(25-35)+AlCl3 neurotoxicity, and expand our current knowledge on the potential beneficial role of caffein to prevent AD progression in subjects environmentally exposed to aluminum.
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Affiliation(s)
- Salvatore Giunta
- Department of Bio-Medical Sciences, Section of Anatomy and Histology, University of Catania, Italy
| | - Violetta Andriolo
- Department of Pediatrics and Public Health Sciences, University of Turin, Italy
| | - Alessandro Castorina
- Department of Bio-Medical Sciences, Section of Anatomy and Histology, University of Catania, Italy.
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Santiago AR, Baptista FI, Santos PF, Cristóvão G, Ambrósio AF, Cunha RA, Gomes CA. Role of microglia adenosine A(2A) receptors in retinal and brain neurodegenerative diseases. Mediators Inflamm 2014; 2014:465694. [PMID: 25132733 PMCID: PMC4124703 DOI: 10.1155/2014/465694] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 06/20/2014] [Indexed: 12/20/2022] Open
Abstract
Neuroinflammation mediated by microglial cells in the brain has been commonly associated with neurodegenerative diseases. Whether this microglia-mediated neuroinflammation is cause or consequence of neurodegeneration is still a matter of controversy. However, it is unequivocal that chronic neuroinflammation plays a role in disease progression and halting that process represents a potential therapeutic strategy. The neuromodulator adenosine emerges as a promising targeting candidate based on its ability to regulate microglial proliferation, chemotaxis, and reactivity through the activation of its G protein coupled A2A receptor (A2AR). This is in striking agreement with the ability of A2AR blockade to control several brain diseases. Retinal degenerative diseases have been also associated with microglia-mediated neuroinflammation, but the role of A2AR has been scarcely explored. This review aims to compare inflammatory features of Parkinson's and Alzheimer's diseases with glaucoma and diabetic retinopathy, discussing the therapeutic potential of A2AR in these degenerative conditions.
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Affiliation(s)
- Ana R. Santiago
- Centre of Ophthalmology and Vision Sciences, IBILI, Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal
- AIBILI, 3000-548 Coimbra, Portugal
- Center for Neuroscience and Cell Biology, Largo Marquês de Pombal, Universidade de Coimbra, 3004-517 Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548 Coimbra, Portugal
| | - Filipa I. Baptista
- Centre of Ophthalmology and Vision Sciences, IBILI, Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal
| | - Paulo F. Santos
- Centre of Ophthalmology and Vision Sciences, IBILI, Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal
- Center for Neuroscience and Cell Biology, Largo Marquês de Pombal, Universidade de Coimbra, 3004-517 Coimbra, Portugal
- Department of Life Sciences, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal
| | - Gonçalo Cristóvão
- Center for Neuroscience and Cell Biology, Largo Marquês de Pombal, Universidade de Coimbra, 3004-517 Coimbra, Portugal
| | - António F. Ambrósio
- Centre of Ophthalmology and Vision Sciences, IBILI, Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal
- AIBILI, 3000-548 Coimbra, Portugal
- Center for Neuroscience and Cell Biology, Largo Marquês de Pombal, Universidade de Coimbra, 3004-517 Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548 Coimbra, Portugal
| | - Rodrigo A. Cunha
- Center for Neuroscience and Cell Biology, Largo Marquês de Pombal, Universidade de Coimbra, 3004-517 Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548 Coimbra, Portugal
| | - Catarina A. Gomes
- Centre of Ophthalmology and Vision Sciences, IBILI, Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal
- Center for Neuroscience and Cell Biology, Largo Marquês de Pombal, Universidade de Coimbra, 3004-517 Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548 Coimbra, Portugal
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Zhang M, Wang H, Zhao J, Chen C, Leak RK, Xu Y, Vosler P, Chen J, Gao Y, Zhang F. Drug-induced hypothermia in stroke models: does it always protect? CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2014; 12:371-80. [PMID: 23469851 DOI: 10.2174/1871527311312030010] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 11/06/2012] [Accepted: 11/11/2012] [Indexed: 12/19/2022]
Abstract
Ischemic stroke is a common neurological disorder lacking a cure. Recent studies show that therapeutic hypothermia is a promising neuroprotective strategy against ischemic brain injury. Several methods to induce therapeutic hypothermia have been established; however, most of them are not clinically feasible for stroke patients. Therefore, pharmacological cooling is drawing increasing attention as a neuroprotective alternative worthy of further clinical development. We begin this review with a brief introduction to the commonly used methods for inducing hypothermia; we then focus on the hypothermic effects of eight classes of hypothermia-inducing drugs: the cannabinoids, opioid receptor activators, transient receptor potential vanilloid, neurotensins, thyroxine derivatives, dopamine receptor activators, hypothermia-inducing gases, adenosine, and adenine nucleotides. Their neuroprotective effects as well as the complications associated with their use are both considered. This article provides guidance for future clinical trials and animal studies on pharmacological cooling in the setting of acute stroke.
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Affiliation(s)
- Meijuan Zhang
- Department of Neurology, University of Pittsburgh School of Medicine, 3500 Terrace Street, Pittsburgh, PA 15213, USA
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Smith MD, Bhatt DP, Geiger JD, Rosenberger TA. Acetate supplementation modulates brain adenosine metabolizing enzymes and adenosine A₂A receptor levels in rats subjected to neuroinflammation. J Neuroinflammation 2014; 11:99. [PMID: 24898794 PMCID: PMC4050445 DOI: 10.1186/1742-2094-11-99] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 05/19/2014] [Indexed: 12/20/2022] Open
Abstract
Background Acetate supplementation reduces neuroglia activation and pro-inflammatory cytokine expression in rat models of neuroinflammation and Lyme neuroborreliosis. Because single-dose glyceryl triacetate (GTA) treatment increases brain phosphocreatine and reduces brain AMP levels, we postulate that GTA modulates adenosine metabolizing enzymes and receptors, which may be a possible mechanism to reduce neuroinflammation. Methods To test this hypothesis, we quantified the ability of GTA to alter brain levels of ecto-5’-nucleotidase (CD73), adenosine kinase (AK), and adenosine A2A receptor using western blot analysis and CD73 activity by measuring the rate of AMP hydrolysis. Neuroinflammation was induced by continuous bacterial lipopolysaccharide (LPS) infusion in the fourth ventricle of the brain for 14 and 28 days. Three treatment strategies were employed, one and two where rats received prophylactic GTA through oral gavage with LPS infusion for 14 or 28 days. In the third treatment regimen, an interventional strategy was used where rats were subjected to 28 days of neuroinflammation, and GTA treatment was started on day 14 following the start of the LPS infusion. Results We found that rats subjected to neuroinflammation for 28 days had a 28% reduction in CD73 levels and a 43% increase in AK levels that was reversed with prophylactic acetate supplementation. CD73 activity in these rats was increased by 46% with the 28-day GTA treatment compared to the water-treated rats. Rats subjected to neuroinflammation for 14 days showed a 50% increase in levels of the adenosine A2A receptor, which was prevented with prophylactic acetate supplementation. Interventional GTA therapy, beginning on day 14 following the induction of neuroinflammation, resulted in a 67% increase in CD73 levels and a 155% increase in adenosine A2A receptor levels. Conclusion These results support the hypothesis that acetate supplementation can modulate brain CD73, AK and adenosine A2A receptor levels, and possibly influence purinergic signaling.
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Affiliation(s)
| | | | | | - Thad A Rosenberger
- Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, 501 North Columbia Road, Grand Forks, North Dakota 58203, USA.
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Increased striatal adenosine A2A receptor levels is an early event in Parkinson's disease-related pathology and it is potentially regulated by miR-34b. Neurobiol Dis 2014; 69:206-14. [PMID: 24892887 DOI: 10.1016/j.nbd.2014.05.030] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 05/01/2014] [Accepted: 05/22/2014] [Indexed: 12/20/2022] Open
Abstract
Adenosine A2A receptor (A2AR) is a G-protein coupled receptor that stimulates adenylyl cyclase activity. In the brain, A2ARs are found highly enriched in striatal GABAergic medium spiny neurons, related to the control of voluntary movement. Pharmacological modulation of A2ARs is particularly useful in Parkinson's disease (PD) due to their property of antagonizing dopamine D2 receptor activity. Increases in A2AR levels have been described in PD patients showing an important loss of dopaminergic denervation markers, but no data have been reported about A2AR levels in incidental PD brains. In the present report, we show that increased A2ARs protein levels were also detected in the putamen of incidental PD cases (Braak PD stages 1-2) with respect to age-matched controls. By contrast, A2ARs mRNA levels remained unchanged, suggesting that posttranslational mechanisms could be involved in the regulation of A2ARs. It has been described how miR-34b/c downregulation is an early event in PD cases. We found that miR-34b levels are also significantly reduced in the putamen of incidental PD cases and along disease progression. Given that 3'UTR of A2AR contains a predicted target site for miR-34b, the potential role of this miRNA in protein A2AR levels was assessed. In vitro studies revealed that endogenous A2AR protein levels increased when miR-34b function was blocked using a specific anti-miR-34b. Moreover, using a luciferase reporter assay with point mutations in a miR-34b predicted binding site within the 3'UTR region of A2AR mRNA abolished the effect of the miRNA using a miR-34b mimic. In addition, we showed a reduced percentage of DNA methylation in the 5'UTR region of ADORA2A in advanced PD cases. Overall, these findings reveal that increased A2AR protein levels occur in asymptomatic PD patients and provide new insights into the molecular mechanisms underlying A2AR expression levels along the progression of this neurodegenerative disease.
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Steger R, Kamal A, Lutchman S, Intrabartolo L, Sohail R, Brumberg JC. Chronic caffeine ingestion causes microglia activation, but not proliferation in the healthy brain. Brain Res Bull 2014; 106:39-46. [PMID: 24881873 DOI: 10.1016/j.brainresbull.2014.05.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 04/22/2014] [Accepted: 05/21/2014] [Indexed: 12/15/2022]
Abstract
Caffeine is the most popular psychoactive drug in the world which contributes to behavioral and metabolic changes when ingested. Within the central nervous system (CNS), caffeine has a high affinity for A1 and A2a adenosine receptors. Serving as an antagonist, caffeine affects the ability of adenosine to bind to these receptors. Caffeine has been shown to alter neuronal functioning through increasing spontaneous firing. However, the effects of caffeine on non-neuronal cells in the CNS have not been studied extensively. Microglia are one phenotype of non-neuronal glia within the CNS. Acting as phagocytes, they contribute to the immune defense system of the brain and express A1 and A2a adenosine receptors. Caffeine, therefore, may affect microglia. In order to test this hypothesis, CD-1 mice were randomly placed into one of three groups: control, low caffeine (0.3 g/L water) and high caffeine (1.0 g/L water) and were allowed to drink freely for 30 days. Following 30 days, brain sections were stained to reveal microglia. Morphological reconstructions and density measurements were examined in cortical and subcortical areas including the primary sensory cortex, primary motor cortex and striatum. Results indicate that microglial density throughout the brain is decreased in the caffeine groups as compared to the control. Caffeine also impacted microglia morphology shortening process length and decreasing branching. These results suggest that chronic caffeine ingestion has a systemic impact on microglia density and their activation.
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Affiliation(s)
- Rob Steger
- The Neuropsychology Doctoral Subprogram (Psychology), The Graduate Center, City University of New York (CUNY), United States
| | - Arifa Kamal
- Neuroscience Major, Queens College, CUNY, United States
| | - Sara Lutchman
- Neuroscience Major, Queens College, CUNY, United States
| | | | - Rabia Sohail
- Psychology Department, Queens College, CUNY, United States
| | - Joshua C Brumberg
- The Neuropsychology Doctoral Subprogram (Psychology), The Graduate Center, City University of New York (CUNY), United States; Neuroscience Major, Queens College, CUNY, United States; Psychology Department, Queens College, CUNY, United States; Neuroscience PhD Subprogram (Biology), The Graduate Center, CUNY, United States.
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Thomas TP, Shih TM. Stimulation of central A1 adenosine receptors suppresses seizure and neuropathology in a soman nerve agent seizure rat model. Toxicol Mech Methods 2014; 24:385-95. [DOI: 10.3109/15376516.2014.920450] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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241
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Machado-Filho JA, Correia AO, Montenegro ABA, Nobre MEP, Cerqueira GS, Neves KRT, Naffah-Mazzacoratti MDG, Cavalheiro EA, de Castro Brito GA, de Barros Viana GS. Caffeine neuroprotective effects on 6-OHDA-lesioned rats are mediated by several factors, including pro-inflammatory cytokines and histone deacetylase inhibitions. Behav Brain Res 2014; 264:116-25. [DOI: 10.1016/j.bbr.2014.01.051] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 01/28/2014] [Accepted: 01/31/2014] [Indexed: 12/20/2022]
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Peripheral blood mononuclear cells as a laboratory to study dementia in the elderly. BIOMED RESEARCH INTERNATIONAL 2014; 2014:169203. [PMID: 24877062 PMCID: PMC4022117 DOI: 10.1155/2014/169203] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 03/28/2014] [Indexed: 02/08/2023]
Abstract
The steady and dramatic increase in the incidence of Alzheimer's disease (AD) and the lack of effective treatments have stimulated the search for strategies to prevent or delay its onset and/or progression. Since the diagnosis of dementia requires a number of established features that are present when the disease is fully developed, but not always in the early stages, the need for a biological marker has proven to be urgent, in terms of both diagnosis and monitoring of AD. AD has been shown to affect peripheral blood mononuclear cells (PBMCs) that are a critical component of the immune system which provide defence against infection. Although studies are continuously supplying additional data that emphasize the central role of inflammation in AD, PBMCs have not been sufficiently investigated in this context. Delineating biochemical alterations in AD blood constituents may prove valuable in identifying accessible footprints that reflect degenerative processes within the Central Nervous System (CNS). In this review, we address the role of biomarkers in AD with a focus on the notion that PBMCs may serve as a peripheral laboratory to find molecular signatures that could aid in differential diagnosis with other forms of dementia and in monitoring of disease progression.
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Yun J, Li J, Zuo Z. Transferred inter-cell ischemic preconditioning-induced neuroprotection may be mediated by adenosine A1 receptors. Brain Res Bull 2014; 103:66-71. [PMID: 24613761 DOI: 10.1016/j.brainresbull.2014.02.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Revised: 02/19/2014] [Accepted: 02/21/2014] [Indexed: 12/20/2022]
Abstract
Ischemic preconditioning-induced neuroprotection is a well-known phenomenon. We hypothesize that this form of neuroprotection is transferable among the same type of cells. To test this hypothesis, human neuroblastoma SH-SY5Y cells were induced to become neuron-like cells. Primary rat cortical neuronal cultures were also used. These cells were subjected to various lengths of short oxygen-glucose deprivation (OGD, an in vitro simulation of ischemia) and then 1-h OGD. Some cells that were not exposed to a short episode of ischemia were incubated with culture medium from the cells that had 3- or 5-min OGD. Those cells were subjected to OGD for 1h at 1 or 24h after they were exposed to the medium. Cell injury was evaluated at 24h after the 1-h OGD by lactate dehydrogenase release assay. In another experiment, cells subjected to a 3-min OGD or exposed to the medium from cells that had a 3-min OGD were harvested at 30min after the OGD or the medium exposure for Western blotting of Akt, a prosurvival protein. Our study showed that a prior episode of ischemia lasting from 3 to 10min significantly reduced the 1-h OGD-induced cell injury. Medium from cells subjected to a 3-min OGD also induced acute and delayed phases of neuroprotection in OGD-naïve human neuron-like cells and primary rat cortical neuronal cultures. Cells subjected to a 3-min OGD or incubated with the medium from cells exposed to a 3-min OGD had increased phosphorylated/activated Akt. The increased phosphorylated Akt and neuroprotection induced by medium transferring were inhibited by 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), an adenosine A1 receptor inhibitor. The 3-min OGD-induced neuroprotection was inhibited by LY294002, an Akt activation inhibitor. These results suggest that ischemic preconditioning-induced neuroprotection is transferable among the cells. Small molecules, such as adenosine, may mediate this effect.
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Affiliation(s)
- Jungyeon Yun
- Department of Anesthesiology, University of Virginia, Charlottesville, VA, United States; Department of Anesthesiology, Research Institute and Hospital, National Cancer Center, Republic of Korea
| | - Jun Li
- Department of Anesthesiology, University of Virginia, Charlottesville, VA, United States; Department of Anesthesiology, Fourth Affiliated Hospital, Harbin Medical University, Harbin 150001, China
| | - Zhiyi Zuo
- Department of Anesthesiology, University of Virginia, Charlottesville, VA, United States.
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Hinton DJ, McGee-Lawrence ME, Lee MR, Kwong HK, Westendorf JJ, Choi DS. Aberrant bone density in aging mice lacking the adenosine transporter ENT1. PLoS One 2014; 9:e88818. [PMID: 24586402 PMCID: PMC3929493 DOI: 10.1371/journal.pone.0088818] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Accepted: 01/17/2014] [Indexed: 12/20/2022] Open
Abstract
Adenosine is known to regulate bone production and resorption in humans and mice. Type 1 equilibrative nucleoside transporter (ENT1) is responsible for the majority of adenosine transport across the plasma membrane and is ubiquitously expressed in both humans and mice. However, the contribution of ENT1-mediated adenosine levels has not been studied in bone remodeling. With the recent identification of the importance of adenosine signaling in bone homeostasis, it is essential to understand the role of ENT1 to develop novel therapeutic compounds for bone disorders. Here we examined the effect of ENT1 deletion on bone density using X-ray, dual energy X-ray absorptiometry and micro-computerized tomography analysis. Our results show that bone density and bone mineral density is reduced in the lower thoracic and lumbar spine as well as the femur of old ENT1 null mice (>7 months) compared to wild-type littermates. Furthermore, we found increased mRNA expression of tartrate-resistant acid phosphatase (TRAP), an osteoclast marker, in isolated long bones from 10 month old ENT1 null mice compared to wild-type mice. In addition, aged ENT1 null mice displayed severe deficit in motor coordination and locomotor activity, which might be attributed to dysregulated bone density. Overall, our study suggests that ENT1-regulated adenosine signaling plays an essential role in lumbar spine and femur bone density.
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Affiliation(s)
- David J. Hinton
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
- Neurobiology of Disease Program, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Meghan E. McGee-Lawrence
- Department of Orthopedic Surgery and Orthopedic Research, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Moonnoh R. Lee
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Hoi K. Kwong
- Advanced Genomics Technology Center, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Jennifer J. Westendorf
- Department of Orthopedic Surgery and Orthopedic Research, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Doo-Sup Choi
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
- Neurobiology of Disease Program, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
- Department of Psychiatry and Psychology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
- * E-mail:
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245
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Nagpure BV, Bian JS. Hydrogen sulfide inhibits A2A adenosine receptor agonist induced β-amyloid production in SH-SY5Y neuroblastoma cells via a cAMP dependent pathway. PLoS One 2014; 9:e88508. [PMID: 24523906 PMCID: PMC3921165 DOI: 10.1371/journal.pone.0088508] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 01/11/2014] [Indexed: 12/20/2022] Open
Abstract
Alzheimer's disease (AD) is the leading cause of senile dementia in today's society. Its debilitating symptoms are manifested by disturbances in many important brain functions, which are influenced by adenosine. Hence, adenosinergic system is considered as a potential therapeutic target in AD treatment. In the present study, we found that sodium hydrosulfide (NaHS, an H2S donor, 100 µM) attenuated HENECA (a selective A2A receptor agonist, 10-200 nM) induced β-amyloid (1-42) (Aβ42) production in SH-SY5Y cells. NaHS also interfered with HENECA-stimulated production and post-translational modification of amyloid precursor protein (APP) by inhibiting its maturation. Measurement of the C-terminal APP fragments generated from its enzymatic cleavage by β-site amyloid precursor protein cleaving enzyme 1 (BACE1) showed that NaHS did not have any significant effect on β-secretase activity. However, the direct measurements of HENECA-elevated γ-secretase activity and mRNA expressions of presenilins suggested that the suppression of Aβ42 production in NaHS pretreated cells was mediated by inhibiting γ-secretase. NaHS induced reductions were accompanied by similar decreases in intracellular cAMP levels and phosphorylation of cAMP responsive element binding protein (CREB). NaHS significantly reduced the elevated cAMP and Aβ42 production caused by forskolin (an adenylyl cyclase, AC agonist) alone or forskolin in combination with IBMX (a phosphodiesterase inhibitor), but had no effect on those caused by IBMX alone. Moreover, pretreatment with NaHS significantly attenuated HENECA-elevated AC activity and mRNA expressions of various AC isoforms. These data suggest that NaHS may preferentially suppress AC activity when it was stimulated. In conclusion, H2S attenuated HENECA induced Aβ42 production in SH-SY5Y neuroblastoma cells through inhibiting γ-secretase via a cAMP dependent pathway.
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Affiliation(s)
- Bhushan Vijay Nagpure
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Jin-Song Bian
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- * E-mail:
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246
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Nguyen MD, Lee ST, Ross AE, Ryals M, Choudhry VI, Venton BJ. Characterization of spontaneous, transient adenosine release in the caudate-putamen and prefrontal cortex. PLoS One 2014; 9:e87165. [PMID: 24494035 PMCID: PMC3907895 DOI: 10.1371/journal.pone.0087165] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 12/19/2013] [Indexed: 12/20/2022] Open
Abstract
Adenosine is a neuroprotective agent that inhibits neuronal activity and modulates neurotransmission. Previous research has shown adenosine gradually accumulates during pathologies such as stroke and regulates neurotransmission on the minute-to-hour time scale. Our lab developed a method using carbon-fiber microelectrodes to directly measure adenosine changes on a sub-second time scale with fast-scan cyclic voltammetry (FSCV). Recently, adenosine release lasting a couple of seconds has been found in murine spinal cord slices. In this study, we characterized spontaneous, transient adenosine release in vivo, in the caudate-putamen and prefrontal cortex of anesthetized rats. The average concentration of adenosine release was 0.17±0.01 µM in the caudate and 0.19±0.01 µM in the prefrontal cortex, although the range was large, from 0.04 to 3.2 µM. The average duration of spontaneous adenosine release was 2.9±0.1 seconds and 2.8±0.1 seconds in the caudate and prefrontal cortex, respectively. The concentration and number of transients detected do not change over a four hour period, suggesting spontaneous events are not caused by electrode implantation. The frequency of adenosine transients was higher in the prefrontal cortex than the caudate-putamen and was modulated by A1 receptors. The A1 antagonist DPCPX (8-cyclopentyl-1,3-dipropylxanthine, 6 mg/kg i.p.) increased the frequency of spontaneous adenosine release, while the A1 agonist CPA (N(6)-cyclopentyladenosine, 1 mg/kg i.p.) decreased the frequency. These findings are a paradigm shift for understanding the time course of adenosine signaling, demonstrating that there is a rapid mode of adenosine signaling that could cause transient, local neuromodulation.
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Affiliation(s)
- Michael D. Nguyen
- Department of Chemistry, University of Virginia, Charlottesville, Virginia, United States of America
| | - Scott T. Lee
- Department of Chemistry, University of Virginia, Charlottesville, Virginia, United States of America
| | - Ashley E. Ross
- Department of Chemistry, University of Virginia, Charlottesville, Virginia, United States of America
| | - Matthew Ryals
- Department of Chemistry, University of Virginia, Charlottesville, Virginia, United States of America
| | - Vishesh I. Choudhry
- Department of Chemistry, University of Virginia, Charlottesville, Virginia, United States of America
| | - B. Jill Venton
- Department of Chemistry, University of Virginia, Charlottesville, Virginia, United States of America
- * E-mail:
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247
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Rial D, Lara DR, Cunha RA. The Adenosine Neuromodulation System in Schizophrenia. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2014; 119:395-449. [DOI: 10.1016/b978-0-12-801022-8.00016-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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248
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Bannon NM, Zhang P, Ilin V, Chistiakova M, Volgushev M. Modulation of synaptic transmission by adenosine in layer 2/3 of the rat visual cortex in vitro. Neuroscience 2013; 260:171-84. [PMID: 24355495 DOI: 10.1016/j.neuroscience.2013.12.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 12/07/2013] [Accepted: 12/09/2013] [Indexed: 12/14/2022]
Abstract
Adenosine is a wide-spread endogenous neuromodulator. In the central nervous system it activates A1 and A2A receptors (A1Rs and A2ARs) which have differential distributions, different affinities to adenosine, are coupled to different G-proteins, and have opposite effects on synaptic transmission. Although effects of adenosine are studied in detail in several brain areas, such as the hippocampus and striatum, the heterogeneity of the effects of A1R and A2AR activation and their differential distribution preclude generalization over brain areas and cell types. Here we study adenosine's effects on excitatory synaptic transmission to layer 2/3 pyramidal neurons in slices of the rat visual cortex. We measured effects of bath application of adenosine receptor ligands on evoked excitatory postsynaptic potentials (EPSPs), miniature excitatory postsynaptic potentials (mEPSPs), and membrane properties. Adenosine reduced the amplitude of evoked EPSPs and excitatory postsynaptic currents (EPSCs), and reduced frequency of mEPSPs in a concentration-dependent and reversible manner. Concurrent with EPSP/C amplitude reduction was an increase in the paired-pulse ratio. These effects were blocked by application of the selective A1R antagonist DPCPX (8-cyclopentyl-1,3-dipropylxanthine), suggesting that activation of presynaptic A1Rs suppresses excitatory transmission by reducing release probability. Adenosine (20μM) hyperpolarized the cell membrane from -65.3±1.5 to -67.7±1.8mV, and reduced input resistance from 396.5±44.4 to 314.0±36.3MOhm (∼20%). These effects were also abolished by DPCPX, suggesting postsynaptic A1Rs. Application of the selective A2AR antagonist SCH-58261 (2-(2-furanyl)-7-(2-phenylethyl)-7H-pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidin-5-a-mine) on the background of high adenosine concentrations revealed an additional decrease in EPSP amplitude. Moreover, application of the A2AR agonist CGS-21680 (4-[2-[[6-amino-9-(N-ethyl-β-d-ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl]benzenepropanoic acid hydrochloride) led to an A1R-dependent increase in mEPSP frequency. Dependence of the A2AR effects on the A1R availability suggests interaction between these receptors, whereby A2ARs exert their facilitatory effect on synaptic transmission by inhibiting the A1R-mediated suppression. Our results demonstrate functional pre and postsynaptic A1Rs and presynaptic A2ARs in layer 2/3 of the visual cortex, and suggest interaction between presynaptic A2ARs and A1Rs.
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Affiliation(s)
- N M Bannon
- Department of Psychology, University of Connecticut, Storrs, CT 06269, USA.
| | - P Zhang
- Department of Psychology, University of Connecticut, Storrs, CT 06269, USA.
| | - V Ilin
- Department of Psychology, University of Connecticut, Storrs, CT 06269, USA.
| | - M Chistiakova
- Department of Psychology, University of Connecticut, Storrs, CT 06269, USA.
| | - M Volgushev
- Department of Psychology, University of Connecticut, Storrs, CT 06269, USA.
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249
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Hubbard JA, Hsu MS, Fiacco TA, Binder DK. Glial cell changes in epilepsy: Overview of the clinical problem and therapeutic opportunities. Neurochem Int 2013; 63:638-51. [DOI: 10.1016/j.neuint.2013.01.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 01/14/2013] [Accepted: 01/18/2013] [Indexed: 12/20/2022]
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250
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Aronica E, Sandau US, Iyer A, Boison D. Glial adenosine kinase--a neuropathological marker of the epileptic brain. Neurochem Int 2013; 63:688-95. [PMID: 23385089 PMCID: PMC3676477 DOI: 10.1016/j.neuint.2013.01.028] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 12/21/2012] [Accepted: 01/27/2013] [Indexed: 12/16/2022]
Abstract
Experimental research over the past decade has supported the critical role of astrocytes activated by different types of injury and the pathophysiological processes that underlie the development of epilepsy. In both experimental and human epileptic tissues astrocytes undergo complex changes in their physiological properties, which can alter glio-neuronal communication, contributing to seizure precipitation and recurrence. In this context, understanding which of the molecular mechanisms are crucially involved in the regulation of glio-neuronal interactions under pathological conditions associated with seizure development is important to get more insight into the role of astrocytes in epilepsy. This article reviews current knowledge regarding the role of glial adenosine kinase as a neuropathological marker of the epileptic brain. Both experimental findings in clinically relevant models, as well as observations in drug-resistant human epilepsies will be discussed, highlighting the link between astrogliosis, dysfunction of adenosine homeostasis and seizure generation and therefore suggesting new strategies for targeting astrocyte-mediated epileptogenesis.
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Affiliation(s)
- Eleonora Aronica
- Department (Neuro) Pathology, Academisch Medisch Centrum, Amsterdam
- Epilepsy Institute in The Netherlands Foundation (Stichting Epilepsie Instellingen Nederland, SEIN), Heemstede, The Netherlands
| | - Ursula S Sandau
- Robert Stone Dow Neurobiology Laboratories, Legacy Research Institute, Portland, OR 97232, USA
| | - Anand Iyer
- Department (Neuro) Pathology, Academisch Medisch Centrum, Amsterdam
| | - Detlev Boison
- Robert Stone Dow Neurobiology Laboratories, Legacy Research Institute, Portland, OR 97232, USA
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