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A 2AR Antagonists Upregulate Expression of GS and GLAST in Rat Hypoxia Model. BIOMED RESEARCH INTERNATIONAL 2020; 2020:2054293. [PMID: 33195689 PMCID: PMC7641686 DOI: 10.1155/2020/2054293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/01/2020] [Accepted: 08/20/2020] [Indexed: 11/18/2022]
Abstract
Background The aim of this study was to research the effects of glutamine synthetase (GS) and glutamate aspartate transporter (GLAST) in rat Müller cells and the effects of an adenosine A2AR antagonist (SCH 442416) on GS and GLAST in hypoxia both in vivo and in vitro. Methods This study used RT-PCR and Western blotting to quantify the expressions of GS and GLAST under different hypoxic conditions as well as the expressions of GS and GLAST at different drug concentrations. A cell viability assay was used to assess drug toxicity. Results mRNA and protein expression of GS and GLAST in hypoxia Group 24 h was significantly increased. mRNA and protein expressions of GS and GLAST both increased in Group 1 μM SCH 442416 compared with other groups. One micromolar SCH 442416 could upregulate GS and GLAST's activity in hypoxia both in vivo and in vitro. Conclusions Hypoxia activates GS and GLAST in rat retinal Müller cells in a short time in vitro. (2) A2AR antagonists upregulate the activity of GS and GLAST in hypoxia both in vivo and in vitro.
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Khalafalla MG, Woods LT, Jasmer KJ, Forti KM, Camden JM, Jensen JL, Limesand KH, Galtung HK, Weisman GA. P2 Receptors as Therapeutic Targets in the Salivary Gland: From Physiology to Dysfunction. Front Pharmacol 2020; 11:222. [PMID: 32231563 PMCID: PMC7082426 DOI: 10.3389/fphar.2020.00222] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 02/18/2020] [Indexed: 12/12/2022] Open
Abstract
Although often overlooked in our daily lives, saliva performs a host of necessary physiological functions, including lubricating and protecting the oral cavity, facilitating taste sensation and digestion and maintaining tooth enamel. Therefore, salivary gland dysfunction and hyposalivation, often resulting from pathogenesis of the autoimmune disease Sjögren's syndrome or from radiotherapy of the head and neck region during cancer treatment, severely reduce the quality of life of afflicted patients and can lead to dental caries, periodontitis, digestive disorders, loss of taste and difficulty speaking. Since their initial discovery in the 1970s, P2 purinergic receptors for extracellular nucleotides, including ATP-gated ion channel P2X and G protein-coupled P2Y receptors, have been shown to mediate physiological processes in numerous tissues, including the salivary glands where P2 receptors represent a link between canonical and non-canonical saliva secretion. Additionally, extracellular nucleotides released during periods of cellular stress and inflammation act as a tissue alarmin to coordinate immunological and tissue repair responses through P2 receptor activation. Accordingly, P2 receptors have gained widespread clinical interest with agonists and antagonists either currently undergoing clinical trials or already approved for human use. Here, we review the contributions of P2 receptors to salivary gland function and describe their role in salivary gland dysfunction. We further consider their potential as therapeutic targets to promote physiological saliva flow, prevent salivary gland inflammation and enhance tissue regeneration.
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Affiliation(s)
- Mahmoud G. Khalafalla
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Lucas T. Woods
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
| | - Kimberly J. Jasmer
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
| | - Kevin Muñoz Forti
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
| | - Jean M. Camden
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
| | - Janicke L. Jensen
- Institute of Clinical Dentistry, Section of Oral Surgery and Oral Medicine, University of Oslo, Oslo, Norway
| | - Kirsten H. Limesand
- Department of Nutritional Sciences, University of Arizona, Tucson, AZ, United States
| | - Hilde K. Galtung
- Institute of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
| | - Gary A. Weisman
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
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von Kügelgen I. Pharmacology of P2Y receptors. Brain Res Bull 2019; 151:12-24. [PMID: 30922852 DOI: 10.1016/j.brainresbull.2019.03.010] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 03/04/2019] [Accepted: 03/17/2019] [Indexed: 01/17/2023]
Abstract
P2Y receptors are G-protein-coupled receptors (GPCRs) for extracellular nucleotides. There are eight mammalian P2Y receptor subtypes divided into two subgroups (P2Y1, P2Y2, P2Y4, P2Y6, and P2Y11) and (P2Y12, P2Y13, and P2Y14). The P2Y receptors are expressed in various cell types and play important roles in physiology and pathophysiology including inflammatory responses and neuropathic pain. The antagonism of P2Y12 receptors is used in pharmacotherapy for the prevention and therapy of cardiovascular events. The nucleoside analogue ticagrelor and active metabolites of the thienopyridine compounds ticlopidine, clopidogrel and prasugrel inhibit platelet P2Y12 receptors and reduce thereby platelet aggregation. The P2Y2 receptor agonist diquafosol is used for the treatment of the dry eye syndrome. The P2Y receptor subtypes differ in their amino acid sequences, their pharmacological profiles and their signaling transduction pathways. Recently, selective receptor ligands have been developed for all subtypes. The published crystal structures of the human P2Y1 and P2Y12 receptors as well as receptor models will facilitate the development of novel drugs for pharmacotherapy.
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Affiliation(s)
- Ivar von Kügelgen
- Department of Pharmacology and Toxicology, Pharma Center, University of Bonn, D-53127, Bonn, Germany.
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von Kügelgen I, Hoffmann K. Pharmacology and structure of P2Y receptors. Neuropharmacology 2015; 104:50-61. [PMID: 26519900 DOI: 10.1016/j.neuropharm.2015.10.030] [Citation(s) in RCA: 163] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 10/22/2015] [Accepted: 10/23/2015] [Indexed: 01/30/2023]
Abstract
P2Y receptors are G-protein-coupled receptors (GPCRs) for extracellular nucleotides. There are eight mammalian P2Y receptor subtypes (P2Y1, P2Y2, P2Y4, P2Y6, P2Y11, P2Y12, P2Y13, and P2Y14). P2Y receptors are widely expressed and play important roles in physiology and pathophysiology. One important example is the ADP-induced platelet aggregation mediated by P2Y1 and P2Y12 receptors. Active metabolites of the thienopyridine compounds ticlopidine, clopidogrel and prasugrel as well as the nucleoside analogue ticagrelor block P2Y12 receptors and thereby platelet aggregation. These drugs are used for the prevention and therapy of cardiovascular events. Moreover, P2Y receptors play important roles in the nervous system. Adenine nucleotides modulate neuronal activity and neuronal fibre outgrowth by activation of P2Y1 receptors and control migration of microglia by P2Y12 receptors. UDP stimulates microglial phagocytosis through activation of P2Y6 receptors. There is evidence for a role for P2Y2 receptors in Alzheimer's disease pathology. The P2Y receptor subtypes are highly diverse in both their amino acid sequences and their pharmacological profiles. Selective receptor ligands have been developed for the pharmacological characterization of the receptor subtypes. The recently published three-dimensional crystal structures of the human P2Y1 and P2Y12 receptors will facilitate the development of therapeutic agents that selectively target P2Y receptors. This article is part of the Special Issue entitled 'Purines in Neurodegeneration and Neuroregeneration'.
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Affiliation(s)
- Ivar von Kügelgen
- Department of Pharmacology and Toxicology, Pharma Center, University of Bonn, D-53127 Bonn, Germany.
| | - Kristina Hoffmann
- Department of Pharmacology and Toxicology, Pharma Center, University of Bonn, D-53127 Bonn, Germany
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Illes P, Verkhratsky A. Purinergic neurone-glia signalling in cognitive-related pathologies. Neuropharmacology 2015; 104:62-75. [PMID: 26256423 DOI: 10.1016/j.neuropharm.2015.08.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 07/19/2015] [Accepted: 08/03/2015] [Indexed: 12/31/2022]
Abstract
Neuroglia, represented by astrocytes, oligodendrocytes, NG glia and microglia are homeostatic, myelinating and defensive cells of the brain. Neuroglial cells express various combinations of purinoceptors, which contribute to multiple intercellular signalling pathways in the healthy and diseased nervous system. Neurological diseases are invariably associated with profound neuroglial remodelling, which is manifest by reactive gliosis, pathological remodelling and functional atrophy of various types of glial cells. Gliopathology is disease and region specific and produces multiple glial phenotypes that may be neuroprotective or neurotoxic. In this review we summarise recent knowledge on the role of glial purinergic signalling in cognitive-related neurological diseases. This article is part of the Special Issue entitled 'Purines in Neurodegeneration and Neuroregeneration'.
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Affiliation(s)
- Peter Illes
- Rudolf Boehm Institute for Pharmacology and Toxicology, University of Leipzig, 04107 Leipzig, Germany.
| | - Alexei Verkhratsky
- Faculty of Life Sciences, The University of Manchester, Manchester, M13 9PT, UK; Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain; Department of Neurosciences, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain; University of Nizhny Novgorod, Nizhny Novgorod 603022, Russia.
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Vecino E, Rodriguez FD, Ruzafa N, Pereiro X, Sharma SC. Glia-neuron interactions in the mammalian retina. Prog Retin Eye Res 2015; 51:1-40. [PMID: 26113209 DOI: 10.1016/j.preteyeres.2015.06.003] [Citation(s) in RCA: 493] [Impact Index Per Article: 54.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 05/18/2015] [Accepted: 06/02/2015] [Indexed: 02/07/2023]
Abstract
The mammalian retina provides an excellent opportunity to study glia-neuron interactions and the interactions of glia with blood vessels. Three main types of glial cells are found in the mammalian retina that serve to maintain retinal homeostasis: astrocytes, Müller cells and resident microglia. Müller cells, astrocytes and microglia not only provide structural support but they are also involved in metabolism, the phagocytosis of neuronal debris, the release of certain transmitters and trophic factors and K(+) uptake. Astrocytes are mostly located in the nerve fibre layer and they accompany the blood vessels in the inner nuclear layer. Indeed, like Müller cells, astrocytic processes cover the blood vessels forming the retinal blood barrier and they fulfil a significant role in ion homeostasis. Among other activities, microglia can be stimulated to fulfil a macrophage function, as well as to interact with other glial cells and neurons by secreting growth factors. This review summarizes the main functional relationships between retinal glial cells and neurons, presenting a general picture of the retina recently modified based on experimental observations. The preferential involvement of the distinct glia cells in terms of the activity in the retina is discussed, for example, while Müller cells may serve as progenitors of retinal neurons, astrocytes and microglia are responsible for synaptic pruning. Since different types of glia participate together in certain activities in the retina, it is imperative to explore the order of redundancy and to explore the heterogeneity among these cells. Recent studies revealed the association of glia cell heterogeneity with specific functions. Finally, the neuroprotective effects of glia on photoreceptors and ganglion cells under normal and adverse conditions will also be explored.
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Affiliation(s)
- Elena Vecino
- Department of Cell Biology and Histology, University of the Basque Country UPV/EHU, Leioa 48940, Vizcaya, Spain
| | - F David Rodriguez
- Department of Biochemistry and Molecular Biology, E-37007, University of Salamanca, Salamanca, Spain
| | - Noelia Ruzafa
- Department of Cell Biology and Histology, University of the Basque Country UPV/EHU, Leioa 48940, Vizcaya, Spain
| | - Xandra Pereiro
- Department of Cell Biology and Histology, University of the Basque Country UPV/EHU, Leioa 48940, Vizcaya, Spain
| | - Sansar C Sharma
- Department of Ophthalmology, Cell Biology and Anatomy, New York Medical College, Valhalla, NY 10595, USA; IKERBASQUE, Basque Foundation for Science at Dept. Cell Biology and Histology, UPV/EHU, Spain
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