The Experts below are selected from a list of 57 Experts worldwide ranked by ideXlab platform
Tobias Engel - One of the best experts on this subject based on the ideXlab platform.
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The Metabotropic Purinergic P2Y Receptor Family as Novel Drug Target in Epilepsy.
Frontiers in pharmacology, 2018Co-Authors: Mariana Alves, Edward Beamer, Tobias EngelAbstract:Epilepsy encompasses a heterogeneous group of neurological syndromes which are characterized by recurrent seizures affecting over 60 million people worldwide. Current anti-epileptic drugs (AEDs) are mainly designed to target ion channels and/or GABA or glutamate Receptors. Despite recent advances in drug development, however, pharmacoresistance in epilepsy remains as high as 30%, suggesting the need for the development of new AEDs with a non-classical mechanism of action. Neuroinflammation is increasingly recognized as one of the key players in seizure generation and in the maintenance of the epileptic phenotype. Consequently, targeting signaling molecules involved in inflammatory processes may represent new avenues to improve treatment in epilepsy. Nucleotides such as adenosine-5'-triphosphate (ATP) and uridine-5'-triphosphate (UTP) are released in the brain into the extracellular space during pathological conditions such as increased neuronal firing or cell death. Once released, these nucleotides bind to and activate specific Purinergic Receptors termed P2 Receptors where they mediate the release of gliotransmitters and drive neuronal hyperexcitation and neuroinflammatory processes. This includes the fast acting ionotropic P2X channels and slower-acting G-protein-coupled P2Y Receptors. While the expression and function of P2X Receptors has been well-established in experimental models of epilepsy, emerging evidence is now also suggesting a prominent role for the P2Y Receptor subfamily in seizure generation and the maintenance of epilepsy. In this review we discuss data supporting a role for the P2Y Receptor family in epilepsy and the most recent finding demonstrating their involvement during seizure-induced pathology and in epilepsy.
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Expression and function of the metabotropic Purinergic P2Y Receptor family in experimental seizure models and patients with drug-refractory epilepsy
Epilepsia, 2017Co-Authors: Mariana Alves, Rosa Gómez-villafuertes, Norman Delanty, Michael Farrell, Donncha F. O’brien, María Teresa Miras-portugal, Miguel Díaz Hernández, David C. Henshall, Tobias EngelAbstract:SummaryObjective ATP is released into the extracellular space during pathologic processes including increased neuronal firing. Once released, ATP acts on P2 Receptors including ionotropic P2X and metabotropic P2Y Receptors, resulting in changes to glial function and neuronal network excitability. Evidence suggests an involvement of P2Y Receptors in the pathogenesis of epilepsy, but there has been no systematic effort to characterize the expression and function of the P2Y Receptor family during seizures and in experimental and human epilepsy. Methods Status epilepticus was induced using either intra-amygdala kainic acid or pilocarpine to characterize the acute- and long-term changes in hippocampal P2Y expression. P2Y expression was also investigated in brain tissue from patients with temporal lobe epilepsy. Finally, we analyzed the effects of two specific P2Y agonists, ADP and UTP, on seizure severity and seizure-induced cell death. Results Both intra-amygdala kainic acid and pilocarpine-induced status epilepticus increased the transcription of the uracil-sensitive P2Y Receptors P2ry2, P2ry4, and P2ry6 and decreased the transcription of the adenine-sensitive P2Y Receptors P2ry1, P2ry12, P2ry13. Protein levels of P2Y1, P2Y2, P2Y4, and P2Y6 were increased after status epilepticus, whereas P2Y12 expression was decreased. In the chronic phase, P2ry1, P2ry2, and P2ry6 transcription and P2Y1, P2Y2, and P2Y12 protein levels were increased with no changes for the other P2Y Receptors. In hippocampal samples from patients with temporal lobe epilepsy, P2Y1 and P2Y2 protein expression was increased, whereas P2Y13 levels were lower. Demonstrating a functional contribution of P2Y Receptors to seizures, central injection of ADP exacerbated seizure severity, whereas treatment with UTP decreased seizure severity during status epilepticus in mice. Significance The present study is the first to establish the specific hippocampal expression profile and function of the P2Y Receptor family after experimental status epilepticus and in human temporal lobe epilepsy and offers potential new targets for seizure control and disease modification.
Jacques Vignon - One of the best experts on this subject based on the ideXlab platform.
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Expression of Purinergic P2Y Receptor subtypes by INS-1 insulinoma beta-cells: a molecular and binding characterization.
European Journal of Pharmacology, 2007Co-Authors: Laura Lugo-garcia, Romain Filhol, Anne-dominique Lajoix, René Gross, Pierre Petit, Jacques VignonAbstract:Purinergic P2Y-Receptor agonists amplify glucose-induced insulin secretion from pancreatic beta-cells, thus offering new opportunities for the treatment of type 2 diabetes. However, little is known about which subtypes of Purinergic P2Y Receptors are expressed in these cells. The INS-1 beta-cell line is used as a model of pancreatic beta-cells, expressing most of their properties. Therefore, we investigated the expression of different molecular subtypes in this cell line by means of real time Polymerase Chain Reaction and Western blot. We also performed a characterization of the binding of a prototypic Purinergic P2Y agonist, Adenosine-5'-O-(1-[(35)S]thiotriphosphate) (ATP-alpha-[(35)S]), to cell membrane homogenates. The molecular analysis evidenced the presence of five different Purinergic P2Y Receptor subtypes (P2Y(1), P2Y(2), P2Y(4), P2Y(6) and P2Y(12)), which were expressed at similar levels. The Western blot analysis allowed detecting corresponding proteins. The binding assay demonstrated a specific ATP-alpha-[(35)S] interaction on high (40%) and low (60%) affinity components. The analysis of ATP-alpha-[(35)S] pharmacological profile on both sites permitted to classify the high affinity binding site as representative of the Purinergic P2Y(1) Receptor subtype and the low affinity binding site of the P2Y(4) and/or P2Y(6) Receptor subtypes. ATP-alpha-S and Adenosine-5'-O-(2-thiodiphosphate) (ADP-beta-S) exhibited opposite selectivity on high and low affinity binding sites.Although Purinergic P2Y(1) Receptor, or a P2Y(1)-like subtype, has been generally considered as that implicated in the modulation of glucose-induced insulin release, the present data show that the beta-cell expresses a complex profile of Purinergic P2Y Receptor subtypes, the functional implication of which remains to be fully elucidated.
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Expression of Purinergic P2Y Receptor subtypes by INS-1 insulinoma β-cells: A molecular and binding characterization
European Journal of Pharmacology, 2007Co-Authors: Laura Lugo-garcia, Romain Filhol, Anne-dominique Lajoix, René Gross, Pierre Petit, Jacques VignonAbstract:Abstract Purinergic P2Y-Receptor agonists amplify glucose-induced insulin secretion from pancreatic β-cells, thus offering new opportunities for the treatment of type 2 diabetes. However, little is known about which subtypes of Purinergic P2Y Receptors are expressed in these cells. The INS-1 β-cell line is used as a model of pancreatic β-cells, expressing most of their properties. Therefore, we investigated the expression of different molecular subtypes in this cell line by means of real time Polymerase Chain Reaction and Western blot. We also performed a characterization of the binding of a prototypic Purinergic P2Y agonist, Adenosine-5′-O-(1-[35S]thiotriphosphate) (ATP-α-[35S]), to cell membrane homogenates. The molecular analysis evidenced the presence of five different Purinergic P2Y Receptor subtypes (P2Y1, P2Y2, P2Y4, P2Y6 and P2Y12), which were expressed at similar levels. The Western blot analysis allowed detecting corresponding proteins. The binding assay demonstrated a specific ATP-α-[35S] interaction on high (40%) and low (60%) affinity components. The analysis of ATP-α-[35S] pharmacological profile on both sites permitted to classify the high affinity binding site as representative of the Purinergic P2Y1 Receptor subtype and the low affinity binding site of the P2Y4 and/or P2Y6 Receptor subtypes. ATP-α-S and Adenosine-5′-O-(2-thiodiphosphate) (ADP-β-S) exhibited opposite selectivity on high and low affinity binding sites.Although Purinergic P2Y1 Receptor, or a P2Y1-like subtype, has been generally considered as that implicated in the modulation of glucose-induced insulin release, the present data show that the β-cell expresses a complex profile of Purinergic P2Y Receptor subtypes, the functional implication of which remains to be fully elucidated.
Mariana Alves - One of the best experts on this subject based on the ideXlab platform.
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context specific switch from anti to pro epileptogenic function of the P2Y1 Receptor in experimental epilepsy
The Journal of Neuroscience, 2019Co-Authors: Mariana Alves, Laura De Diego Garcia, Giorgia Conte, Eva M Jimenezmateos, Beatrice Dorsi, Amaya Sanzrodriguez, Jochen H M Prehn, David C. HenshallAbstract:Extracellular ATP activates inflammatory responses to tissue injury. It is also implicated in establishing lasting network hyperexcitability in the brain by acting upon independent Receptor systems. Whereas the fast-acting P2X channels have well-established roles driving neuroinflammation and increasing hyperexcitability, the slower-acting metabotropic P2Y Receptors have received much less attention. Recent studies of P2Y1 Receptor function in seizures and epilepsy have produced contradictory results, suggesting that the role of this Receptor during seizure pathology may be highly sensitive to context. Here, by using male mice, we demonstrate that the metabotropic P2Y1 Receptor mediates either proconvulsive or anticonvulsive responses, dependent on the time point of activation in relation to the induction of status epilepticus. P2Y1 deficiency or a P2Y1 antagonist (MRS2500) administered before a chemoconvulsant, exacerbates epileptiform activity, whereas a P2Y1 agonist (MRS2365) administered at this time point is anticonvulsant. When these drugs are administered after the onset of status epilepticus, however, their effect on seizure severity is reversed, with the antagonist now anticonvulsant and the agonist proconvulsant. This result was consistent across two different mouse models of status epilepticus (intra-amygdala kainic acid and intraperitoneal pilocarpine). Pharmacologic P2Y1 blockade during status epilepticus reduces also associated brain damage, delays the development of epilepsy and, when applied during epilepsy, suppresses spontaneous seizures, in mice. Our data show a context-specific role for P2Y1 during seizure pathology and demonstrate that blocking P2Y1 after status epilepticus and during epilepsy has potent anticonvulsive effects, suggesting that P2Y1 may be a novel candidate for the treatment of drug-refractory status epilepticus and epilepsy. SIGNIFICANCE STATEMENT This is the first study to fully characterize the contribution of a metabotropic Purinergic P2Y Receptor during acute seizures and epilepsy. The findings suggest that targeting P2Y1 may offer a potential novel treatment strategy for drug-refractory status epilepticus and epilepsy. Our data demonstrate a context-specific role of P2Y1 activation during seizures, switching from a proconvulsive to an anticonvulsive role depending on physiopathological context. Thus, our study provides a possible explanation for seemingly conflicting results obtained between studies of different brain diseases where P2Y1 targeting has been proposed as a potential treatment strategy and highlights that the timing of pharmacological interventions is of critical importance to the understanding of how Receptors contribute to the generation of seizures and the development of epilepsy.
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The Metabotropic Purinergic P2Y Receptor Family as Novel Drug Target in Epilepsy.
Frontiers in pharmacology, 2018Co-Authors: Mariana Alves, Edward Beamer, Tobias EngelAbstract:Epilepsy encompasses a heterogeneous group of neurological syndromes which are characterized by recurrent seizures affecting over 60 million people worldwide. Current anti-epileptic drugs (AEDs) are mainly designed to target ion channels and/or GABA or glutamate Receptors. Despite recent advances in drug development, however, pharmacoresistance in epilepsy remains as high as 30%, suggesting the need for the development of new AEDs with a non-classical mechanism of action. Neuroinflammation is increasingly recognized as one of the key players in seizure generation and in the maintenance of the epileptic phenotype. Consequently, targeting signaling molecules involved in inflammatory processes may represent new avenues to improve treatment in epilepsy. Nucleotides such as adenosine-5'-triphosphate (ATP) and uridine-5'-triphosphate (UTP) are released in the brain into the extracellular space during pathological conditions such as increased neuronal firing or cell death. Once released, these nucleotides bind to and activate specific Purinergic Receptors termed P2 Receptors where they mediate the release of gliotransmitters and drive neuronal hyperexcitation and neuroinflammatory processes. This includes the fast acting ionotropic P2X channels and slower-acting G-protein-coupled P2Y Receptors. While the expression and function of P2X Receptors has been well-established in experimental models of epilepsy, emerging evidence is now also suggesting a prominent role for the P2Y Receptor subfamily in seizure generation and the maintenance of epilepsy. In this review we discuss data supporting a role for the P2Y Receptor family in epilepsy and the most recent finding demonstrating their involvement during seizure-induced pathology and in epilepsy.
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Expression and function of the metabotropic Purinergic P2Y Receptor family in experimental seizure models and patients with drug-refractory epilepsy
Epilepsia, 2017Co-Authors: Mariana Alves, Rosa Gómez-villafuertes, Norman Delanty, Michael Farrell, Donncha F. O’brien, María Teresa Miras-portugal, Miguel Díaz Hernández, David C. Henshall, Tobias EngelAbstract:SummaryObjective ATP is released into the extracellular space during pathologic processes including increased neuronal firing. Once released, ATP acts on P2 Receptors including ionotropic P2X and metabotropic P2Y Receptors, resulting in changes to glial function and neuronal network excitability. Evidence suggests an involvement of P2Y Receptors in the pathogenesis of epilepsy, but there has been no systematic effort to characterize the expression and function of the P2Y Receptor family during seizures and in experimental and human epilepsy. Methods Status epilepticus was induced using either intra-amygdala kainic acid or pilocarpine to characterize the acute- and long-term changes in hippocampal P2Y expression. P2Y expression was also investigated in brain tissue from patients with temporal lobe epilepsy. Finally, we analyzed the effects of two specific P2Y agonists, ADP and UTP, on seizure severity and seizure-induced cell death. Results Both intra-amygdala kainic acid and pilocarpine-induced status epilepticus increased the transcription of the uracil-sensitive P2Y Receptors P2ry2, P2ry4, and P2ry6 and decreased the transcription of the adenine-sensitive P2Y Receptors P2ry1, P2ry12, P2ry13. Protein levels of P2Y1, P2Y2, P2Y4, and P2Y6 were increased after status epilepticus, whereas P2Y12 expression was decreased. In the chronic phase, P2ry1, P2ry2, and P2ry6 transcription and P2Y1, P2Y2, and P2Y12 protein levels were increased with no changes for the other P2Y Receptors. In hippocampal samples from patients with temporal lobe epilepsy, P2Y1 and P2Y2 protein expression was increased, whereas P2Y13 levels were lower. Demonstrating a functional contribution of P2Y Receptors to seizures, central injection of ADP exacerbated seizure severity, whereas treatment with UTP decreased seizure severity during status epilepticus in mice. Significance The present study is the first to establish the specific hippocampal expression profile and function of the P2Y Receptor family after experimental status epilepticus and in human temporal lobe epilepsy and offers potential new targets for seizure control and disease modification.
Laura Lugo-garcia - One of the best experts on this subject based on the ideXlab platform.
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Expression of Purinergic P2Y Receptor subtypes by INS-1 insulinoma beta-cells: a molecular and binding characterization.
European Journal of Pharmacology, 2007Co-Authors: Laura Lugo-garcia, Romain Filhol, Anne-dominique Lajoix, René Gross, Pierre Petit, Jacques VignonAbstract:Purinergic P2Y-Receptor agonists amplify glucose-induced insulin secretion from pancreatic beta-cells, thus offering new opportunities for the treatment of type 2 diabetes. However, little is known about which subtypes of Purinergic P2Y Receptors are expressed in these cells. The INS-1 beta-cell line is used as a model of pancreatic beta-cells, expressing most of their properties. Therefore, we investigated the expression of different molecular subtypes in this cell line by means of real time Polymerase Chain Reaction and Western blot. We also performed a characterization of the binding of a prototypic Purinergic P2Y agonist, Adenosine-5'-O-(1-[(35)S]thiotriphosphate) (ATP-alpha-[(35)S]), to cell membrane homogenates. The molecular analysis evidenced the presence of five different Purinergic P2Y Receptor subtypes (P2Y(1), P2Y(2), P2Y(4), P2Y(6) and P2Y(12)), which were expressed at similar levels. The Western blot analysis allowed detecting corresponding proteins. The binding assay demonstrated a specific ATP-alpha-[(35)S] interaction on high (40%) and low (60%) affinity components. The analysis of ATP-alpha-[(35)S] pharmacological profile on both sites permitted to classify the high affinity binding site as representative of the Purinergic P2Y(1) Receptor subtype and the low affinity binding site of the P2Y(4) and/or P2Y(6) Receptor subtypes. ATP-alpha-S and Adenosine-5'-O-(2-thiodiphosphate) (ADP-beta-S) exhibited opposite selectivity on high and low affinity binding sites.Although Purinergic P2Y(1) Receptor, or a P2Y(1)-like subtype, has been generally considered as that implicated in the modulation of glucose-induced insulin release, the present data show that the beta-cell expresses a complex profile of Purinergic P2Y Receptor subtypes, the functional implication of which remains to be fully elucidated.
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Expression of Purinergic P2Y Receptor subtypes by INS-1 insulinoma β-cells: A molecular and binding characterization
European Journal of Pharmacology, 2007Co-Authors: Laura Lugo-garcia, Romain Filhol, Anne-dominique Lajoix, René Gross, Pierre Petit, Jacques VignonAbstract:Abstract Purinergic P2Y-Receptor agonists amplify glucose-induced insulin secretion from pancreatic β-cells, thus offering new opportunities for the treatment of type 2 diabetes. However, little is known about which subtypes of Purinergic P2Y Receptors are expressed in these cells. The INS-1 β-cell line is used as a model of pancreatic β-cells, expressing most of their properties. Therefore, we investigated the expression of different molecular subtypes in this cell line by means of real time Polymerase Chain Reaction and Western blot. We also performed a characterization of the binding of a prototypic Purinergic P2Y agonist, Adenosine-5′-O-(1-[35S]thiotriphosphate) (ATP-α-[35S]), to cell membrane homogenates. The molecular analysis evidenced the presence of five different Purinergic P2Y Receptor subtypes (P2Y1, P2Y2, P2Y4, P2Y6 and P2Y12), which were expressed at similar levels. The Western blot analysis allowed detecting corresponding proteins. The binding assay demonstrated a specific ATP-α-[35S] interaction on high (40%) and low (60%) affinity components. The analysis of ATP-α-[35S] pharmacological profile on both sites permitted to classify the high affinity binding site as representative of the Purinergic P2Y1 Receptor subtype and the low affinity binding site of the P2Y4 and/or P2Y6 Receptor subtypes. ATP-α-S and Adenosine-5′-O-(2-thiodiphosphate) (ADP-β-S) exhibited opposite selectivity on high and low affinity binding sites.Although Purinergic P2Y1 Receptor, or a P2Y1-like subtype, has been generally considered as that implicated in the modulation of glucose-induced insulin release, the present data show that the β-cell expresses a complex profile of Purinergic P2Y Receptor subtypes, the functional implication of which remains to be fully elucidated.
Mehmet Ugur - One of the best experts on this subject based on the ideXlab platform.
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Cell adhesion modulates 5-HT(1D) and P2Y Receptor signal trafficking differentially in LTK-8 cells.
European journal of pharmacology, 2008Co-Authors: Figen Amber-cicek, Ozlem Ugur, Kemal Sayar, Mehmet UgurAbstract:In this study, we investigated adhesion-induced changes in cellular responses to serotonin 5-HT(1D) and Purinergic P2Y Receptor stimulation. We demonstrated that detachment of LTK-8 cells increased 5-HT(1D) Receptor-mediated intracellular Ca(2+) and extracellular signal regulated kinase (ERK) phosphorylation responses without affecting the adenylate cyclase response. Additionally, detachment enabled 5-HT(1D) Receptor stimulation to inhibit P2Y Receptor-induced [Ca(2+)](i) mobilization. Such a cross talk between the two Receptor systems was not observed in attached cells. P2Y Receptor-induced Ca(2+) response was insensitive to adhesion state of the cells, while ERK phosphorylation response was enhanced upon detachment. Integrity of the actin cytoskeleton did not appear to play a role in adhesion sensitivity of 5-HT(1D)-mediated responses, as treatment of attached cells with cytochalasin D did not mimic detachment-induced effects. Effects of detachment were reversed immediately after re-attachment of the suspended cells on poly-l-lysine coated cover slips, suggesting that the involvement of integrins or focal adhesion complexes is unlikely. Taken collectively, our results demonstrate that not only cellular responses induced by different G protein-coupled Receptors, but also different responses induced by a particular G protein-coupled Receptor, can be affected differentially by the adhesion status of cells. This suggests an important role for cell adhesion in controlling the coupling of a single G protein-coupled Receptor to different intracellular responses.
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Cell adhesion modulates 5-HT1D and P2Y Receptor signal trafficking differentially in LTK-8 cells
European Journal of Pharmacology, 2008Co-Authors: Figen Amber-cicek, Ozlem Ugur, Kemal Sayar, Mehmet UgurAbstract:Abstract In this study, we investigated adhesion-induced changes in cellular responses to serotonin 5-HT 1D and Purinergic P2Y Receptor stimulation. We demonstrated that detachment of LTK-8 cells increased 5-HT 1D Receptor-mediated intracellular Ca 2+ and extracellular signal regulated kinase (ERK) phosphorylation responses without affecting the adenylate cyclase response. Additionally, detachment enabled 5-HT 1D Receptor stimulation to inhibit P2Y Receptor-induced [Ca 2+ ] i mobilization. Such a cross talk between the two Receptor systems was not observed in attached cells. P2Y Receptor-induced Ca 2+ response was insensitive to adhesion state of the cells, while ERK phosphorylation response was enhanced upon detachment. Integrity of the actin cytoskeleton did not appear to play a role in adhesion sensitivity of 5-HT 1D -mediated responses, as treatment of attached cells with cytochalasin D did not mimic detachment-induced effects. Effects of detachment were reversed immediately after re-attachment of the suspended cells on poly- l -lysine coated cover slips, suggesting that the involvement of integrins or focal adhesion complexes is unlikely. Taken collectively, our results demonstrate that not only cellular responses induced by different G protein-coupled Receptors, but also different responses induced by a particular G protein-coupled Receptor, can be affected differentially by the adhesion status of cells. This suggests an important role for cell adhesion in controlling the coupling of a single G protein-coupled Receptor to different intracellular responses.
