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Leite-Aguiar R, Bello-Santos VG, Castro NG, Coutinho-Silva R, Savio LEB. Techniques for evaluating the ATP-gated ion channel P2X7 receptor function in macrophages and microglial cells. J Immunol Methods 2024; 532:113727. [PMID: 38997100 DOI: 10.1016/j.jim.2024.113727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 05/31/2024] [Accepted: 07/08/2024] [Indexed: 07/14/2024]
Abstract
Resident macrophages are tissue-specific innate immune cells acting as sentinels, constantly patrolling their assigned tissue to maintain homeostasis, and quickly responding to pathogenic invaders or molecular danger signals molecules when necessary. Adenosine triphosphate (ATP), when released to the extracellular medium, acts as a danger signal through specific purinergic receptors. Interaction of ATP with the purinergic receptor P2X7 activates macrophages and microglial cells in different pathological conditions, triggering inflammation. The highly expressed P2X7 receptor in these cells induces cell membrane permeabilization, inflammasome activation, cell death, and the production of inflammatory mediators, including cytokines and nitrogen and oxygen-reactive species. This review explores the techniques to evaluate the functional and molecular aspects of the P2X7 receptor, particularly in macrophages and microglial cells. Polymerase chain reaction (PCR), Western blotting, and immunocytochemistry or immunohistochemistry are essential for assessing gene and protein expression in these cell types. Evaluation of P2X7 receptor function involves the use of ATP and selective agonists and antagonists and diverse techniques, including electrophysiology, intracellular calcium measurements, ethidium bromide uptake, and propidium iodide cell viability assays. These techniques are crucial for studying the role of P2X7 receptors in immune responses, neuroinflammation, and various pathological conditions. Therefore, a comprehensive understanding of the functional and molecular aspects of the P2X7 receptor in macrophages and microglia is vital for unraveling its involvement in immune modulation and its potential as a therapeutic target. The methodologies presented and discussed herein offer valuable tools for researchers investigating the complexities of P2X7 receptor signaling in innate immune cells in health and disease.
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Affiliation(s)
- Raíssa Leite-Aguiar
- Laboratório de Imunofisiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | | | - Robson Coutinho-Silva
- Laboratório de Imunofisiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Luiz Eduardo Baggio Savio
- Laboratório de Imunofisiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil..
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2
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Sluyter R, Adriouch S, Fuller SJ, Nicke A, Sophocleous RA, Watson D. Animal Models for the Investigation of P2X7 Receptors. Int J Mol Sci 2023; 24:ijms24098225. [PMID: 37175933 PMCID: PMC10179175 DOI: 10.3390/ijms24098225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 04/21/2023] [Accepted: 04/27/2023] [Indexed: 05/15/2023] Open
Abstract
The P2X7 receptor is a trimeric ligand-gated cation channel activated by extracellular adenosine 5'-triphosphate. The study of animals has greatly advanced the investigation of P2X7 and helped to establish the numerous physiological and pathophysiological roles of this receptor in human health and disease. Following a short overview of the P2X7 distribution, roles and functional properties, this article discusses how animal models have contributed to the generation of P2X7-specific antibodies and nanobodies (including biologics), recombinant receptors and radioligands to study P2X7 as well as to the pharmacokinetic testing of P2X7 antagonists. This article then outlines how mouse and rat models have been used to study P2X7. These sections include discussions on preclinical disease models, polymorphic P2X7 variants, P2X7 knockout mice (including bone marrow chimeras and conditional knockouts), P2X7 reporter mice, humanized P2X7 mice and P2X7 knockout rats. Finally, this article reviews the limited number of studies involving guinea pigs, rabbits, monkeys (rhesus macaques), dogs, cats, zebrafish, and other fish species (seabream, ayu sweetfish, rainbow trout and Japanese flounder) to study P2X7.
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Affiliation(s)
- Ronald Sluyter
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Sahil Adriouch
- UniRouen, INSERM, U1234, Pathophysiology, Autoimmunity, and Immunotherapy, (PANTHER), Univ Rouen Normandie, University of Rouen, F-76000 Rouen, France
| | - Stephen J Fuller
- Sydney Medical School Nepean, Faculty of Medicine and Health, The University of Sydney, Nepean Hospital, Kingswood, NSW 2750, Australia
| | - Annette Nicke
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, 80336 Munich, Germany
| | - Reece A Sophocleous
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Debbie Watson
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
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3
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Sluyter R, Sophocleous RA, Stokes L. P2X receptors: Insights from the study of the domestic dog. Neuropharmacology 2023; 224:109358. [PMID: 36464207 DOI: 10.1016/j.neuropharm.2022.109358] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 11/23/2022] [Accepted: 11/28/2022] [Indexed: 12/03/2022]
Abstract
Fifty years ago, the late Geoffrey Burnstock described the concept of purinergic nerves and transmission bringing into existence the broader concepts of purinergic signaling including P2X receptors. These receptors are trimeric ligand-gated cation channels activated by extracellular adenosine 5'-triphosphate (ATP). P2X receptors have important roles in health and disease and continue to gain interest as potential therapeutic targets in inflammatory, neurological, cardiovascular and many other disorders including cancer. Current understanding of P2X receptors has largely arisen from the study of these receptors in humans and rodents, but additional insights have been obtained from the study of P2X receptors in the domestic dog, Canis familiaris. This review article will briefly introduce purinergic signaling and P2X receptors, before detailing the pharmacological profiles of the two recombinant canine P2X receptors studied to date, P2X7 and P2X4. The article will then describe the current state of knowledge concerning the distribution and function of the P2X receptor family in dogs. The article will also discuss the characterization of single nucleotide polymorphisms in the canine P2RX7 gene, and contrast this variation to the canine P2RX4 gene, which is largely conserved between dogs. Finally, this article will outline published examples of the use of dogs to study the pharmacokinetics of P2X7 and P2X3 antagonists, and how they have contributed to the preclinical testing of antagonists to human P2X7, CE-224,535, and human P2X3, Gefapixant (AF-219, MK-7264) and Eliapixant (BAY, 1817080), with Gefapixant gaining recent approval for use in the treatment of refractory chronic cough in humans. This article is part of the Special Issue on 'Purinergic Signaling: 50 years'.
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Affiliation(s)
- Ronald Sluyter
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia; Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia.
| | - Reece A Sophocleous
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia; Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Leanne Stokes
- School of Pharmacy, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
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4
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6-Furopyridine Hexamethylene Amiloride Is a Non-Selective P2X7 Receptor Antagonist. Biomolecules 2022; 12:biom12091309. [PMID: 36139148 PMCID: PMC9496321 DOI: 10.3390/biom12091309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 09/12/2022] [Accepted: 09/13/2022] [Indexed: 11/17/2022] Open
Abstract
P2X7 is an extracellular adenosine 5′-triphopshate (ATP)-gated cation channel present on leukocytes, where its activation induces pro-inflammatory cytokine release and ectodomain shedding of cell surface molecules. Human P2X7 can be partially inhibited by amiloride and its derivatives at micromolar concentrations. This study aimed to screen a library of compounds derived from amiloride or its derivative 5-(N,N-hexamethylene) amiloride (HMA) to identify a potential P2X7 antagonist. 6-Furopyridine HMA (6-FPHMA) was identified as a novel P2X7 antagonist and was characterized further. 6-FPHMA impaired ATP-induced dye uptake into human RPMI8226 multiple myeloma cells and human P2X7-HEK293 cells, in a concentration-dependent, non-competitive manner. Likewise, 6-FPHMA blocked ATP-induced Ca2+ fluxes in human P2X7-HEK293 cells in a concentration-dependent, non-competitive manner. 6-FPHMA inhibited ATP-induced dye uptake into human T cells, and interleukin-1β release within human blood and CD23 shedding from RPMI8226 cells. 6-FPHMA also impaired ATP-induced dye uptake into murine P2X7- and canine P2X7-HEK293 cells. However, 6-FPHMA impaired ATP-induced Ca2+ fluxes in human P2X4-HEK293 cells and non-transfected HEK293 cells, which express native P2Y1, P2Y2 and P2Y4. In conclusion, 6-FPHMA inhibits P2X7 from multiple species. Its poor selectivity excludes its use as a specific P2X7 antagonist, but further study of amiloride derivatives as P2 receptor antagonists is warranted.
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Jiang LH, Caseley EA, Muench SP, Roger S. Structural basis for the functional properties of the P2X7 receptor for extracellular ATP. Purinergic Signal 2021; 17:331-344. [PMID: 33987781 PMCID: PMC8410900 DOI: 10.1007/s11302-021-09790-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 04/19/2021] [Indexed: 02/06/2023] Open
Abstract
The P2X7 receptor, originally known as the P2Z receptor due to its distinctive functional properties, has a structure characteristic of the ATP-gated ion channel P2X receptor family. The P2X7 receptor is an important mediator of ATP-induced purinergic signalling and is involved the pathogenesis of numerous conditions as well as in the regulation of diverse physiological functions. Functional characterisations, in conjunction with site-directed mutagenesis, molecular modelling, and, recently, structural determination, have provided significant insights into the structure–function relationships of the P2X7 receptor. This review discusses the current understanding of the structural basis for the functional properties of the P2X7 receptor.
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Affiliation(s)
- Lin-Hua Jiang
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK.
| | - Emily A Caseley
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK
- Faculty of Medicine and Health, Leeds Institute of Rheumatic and Musculoskeletal Medicine, St James's University Hospital, Leeds, UK
| | - Steve P Muench
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Sébastien Roger
- EA4245, Transplantation, Immunology and Inflammation, Faculty of Medicine, University of Tours, Tours, France
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6
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Martínez-Cuesta MÁ, Blanch-Ruiz MA, Ortega-Luna R, Sánchez-López A, Álvarez Á. Structural and Functional Basis for Understanding the Biological Significance of P2X7 Receptor. Int J Mol Sci 2020; 21:ijms21228454. [PMID: 33182829 PMCID: PMC7696479 DOI: 10.3390/ijms21228454] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/04/2020] [Accepted: 11/06/2020] [Indexed: 12/11/2022] Open
Abstract
The P2X7 receptor (P2X7R) possesses a unique structure associated to an as yet not fully understood mechanism of action that facilitates cell permeability to large ionic molecules through the receptor itself and/or nearby membrane proteins. High extracellular adenosine triphosphate (ATP) levels—inexistent in physiological conditions—are required for the receptor to be triggered and contribute to its role in cell damage signaling. The inconsistent data on its activation pathways and the few studies performed in natively expressed human P2X7R have led us to review the structure, activation pathways, and specific cellular location of P2X7R in order to analyze its biological relevance. The ATP-gated P2X7R is a homo-trimeric receptor channel that is occasionally hetero-trimeric and highly polymorphic, with at least nine human splice variants. It is localized predominantly in the cellular membrane and has a characteristic plasticity due to an extended C-termini, which confers it the capacity of interacting with membrane structural compounds and/or intracellular signaling messengers to mediate flexible transduction pathways. Diverse drugs and a few endogenous molecules have been highlighted as extracellular allosteric modulators of P2X7R. Therefore, studies in human cells that constitutively express P2X7R need to investigate the precise endogenous mediator located nearby the activation/modulation domains of the receptor. Such research could help us understand the possible physiological ATP-mediated P2X7R homeostasis signaling.
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Affiliation(s)
- María Ángeles Martínez-Cuesta
- Departamento de Farmacología, Facultad de Medicina y Odontología, Universidad de Valencia, 46010 Valencia, Spain; (M.A.B.-R.); (R.O.-L.); (A.S.-L.)
- CIBERehd, Valencia, Spain
- Correspondence: (M.Á.M.-C.); (Á.Á.); Tel.: +34-963983716 (M.Á.M.-C.); +34-963864898 (Á.Á.)
| | - María Amparo Blanch-Ruiz
- Departamento de Farmacología, Facultad de Medicina y Odontología, Universidad de Valencia, 46010 Valencia, Spain; (M.A.B.-R.); (R.O.-L.); (A.S.-L.)
| | - Raquel Ortega-Luna
- Departamento de Farmacología, Facultad de Medicina y Odontología, Universidad de Valencia, 46010 Valencia, Spain; (M.A.B.-R.); (R.O.-L.); (A.S.-L.)
| | - Ainhoa Sánchez-López
- Departamento de Farmacología, Facultad de Medicina y Odontología, Universidad de Valencia, 46010 Valencia, Spain; (M.A.B.-R.); (R.O.-L.); (A.S.-L.)
| | - Ángeles Álvarez
- Departamento de Farmacología, Facultad de Medicina y Odontología, Universidad de Valencia, 46010 Valencia, Spain; (M.A.B.-R.); (R.O.-L.); (A.S.-L.)
- CIBERehd, Valencia, Spain
- Correspondence: (M.Á.M.-C.); (Á.Á.); Tel.: +34-963983716 (M.Á.M.-C.); +34-963864898 (Á.Á.)
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7
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Rivas-Yáñez E, Barrera-Avalos C, Parra-Tello B, Briceño P, Rosemblatt MV, Saavedra-Almarza J, Rosemblatt M, Acuña-Castillo C, Bono MR, Sauma D. P2X7 Receptor at the Crossroads of T Cell Fate. Int J Mol Sci 2020; 21:E4937. [PMID: 32668623 PMCID: PMC7404255 DOI: 10.3390/ijms21144937] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 06/26/2020] [Accepted: 07/07/2020] [Indexed: 02/06/2023] Open
Abstract
The P2X7 receptor is a ligand-gated, cation-selective channel whose main physiological ligand is ATP. P2X7 receptor activation may also be triggered by ARTC2.2-dependent ADP ribosylation in the presence of extracellular NAD. Upon activation, this receptor induces several responses, including the influx of calcium and sodium ions, phosphatidylserine externalization, the formation of a non-selective membrane pore, and ultimately cell death. P2X7 receptor activation depends on the availability of extracellular nucleotides, whose concentrations are regulated by the action of extracellular nucleotidases such as CD39 and CD38. The P2X7 receptor has been extensively studied in the context of the immune response, and it has been reported to be involved in inflammasome activation, cytokine production, and the migration of different innate immune cells in response to ATP. In adaptive immune responses, the P2X7 receptor has been linked to T cell activation, differentiation, and apoptosis induction. In this review, we will discuss the evidence of the role of the P2X7 receptor on T cell differentiation and in the control of T cell responses in inflammatory conditions.
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Affiliation(s)
- Elizabeth Rivas-Yáñez
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago 7800003, Chile; (E.R.-Y.); (B.P.-T.); (P.B.); (M.V.R.); (J.S.-A.); (M.R.)
| | - Carlos Barrera-Avalos
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago 9160000, Chile;
| | - Brian Parra-Tello
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago 7800003, Chile; (E.R.-Y.); (B.P.-T.); (P.B.); (M.V.R.); (J.S.-A.); (M.R.)
| | - Pedro Briceño
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago 7800003, Chile; (E.R.-Y.); (B.P.-T.); (P.B.); (M.V.R.); (J.S.-A.); (M.R.)
| | - Mariana V. Rosemblatt
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago 7800003, Chile; (E.R.-Y.); (B.P.-T.); (P.B.); (M.V.R.); (J.S.-A.); (M.R.)
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago 7510157, Chile
| | - Juan Saavedra-Almarza
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago 7800003, Chile; (E.R.-Y.); (B.P.-T.); (P.B.); (M.V.R.); (J.S.-A.); (M.R.)
| | - Mario Rosemblatt
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago 7800003, Chile; (E.R.-Y.); (B.P.-T.); (P.B.); (M.V.R.); (J.S.-A.); (M.R.)
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago 7510157, Chile
- Fundación Ciencia & Vida, Santiago 7780272, Chile
| | - Claudio Acuña-Castillo
- Centro de Biotecnología Acuícola, Universidad de Santiago de Chile, Santiago 9160000, Chile
| | - María Rosa Bono
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago 7800003, Chile; (E.R.-Y.); (B.P.-T.); (P.B.); (M.V.R.); (J.S.-A.); (M.R.)
| | - Daniela Sauma
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago 7800003, Chile; (E.R.-Y.); (B.P.-T.); (P.B.); (M.V.R.); (J.S.-A.); (M.R.)
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8
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Duan H, Ni S, Yang S, Zhou Y, Zhang Y, Zhang S. Conservation of eATP perception throughout multicellular animal evolution: Identification and functional characterization of coral and amphioxus P2X7-like receptors and flounder P2X7 receptor. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 106:103641. [PMID: 32045589 DOI: 10.1016/j.dci.2020.103641] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 02/07/2020] [Accepted: 02/07/2020] [Indexed: 06/10/2023]
Abstract
Perception of extracellular ATP (eATP), a common endogenous damage-associated molecular pattern, is through its receptor P2X7R. If eATP/P2X7R signaling is conserved throughout animal evolution is unknown. Moreover, little information is currently available regarding P2X7R in invertebrates. Here we demonstrated that the coral P2X7-like receptor, AdP2X7RL, the amphioxus P2X7-like receptor, BjP2X7RL and the flounder P2X7 receptor, PoP2X7R, shared common features characteristic of mammalian P2X7R, and their 3D structures displayed high resemblance to that of human P2X7R. Expression of Adp2x7rl, Bjp2x7rl and Pop2x7r was all subjected to the regulation by LPS and ATP. We also showed that AdP2X7RL, BjP2X7RL and PoP2X7R were distributed on the plasma membrane in AdP2X7RL-, BjP2X7RL- and PoP2X7R-expressing HEK cells, and had strong affinity to eATP. Importantly, the binding of AdP2X7RL, BjP2X7RL and PoP2X7R to eATP all induced similar downstream responses, including induction of cytokines (IL-1β, IL-6, IL-8 and CCL-2), enhancement of phagocytosis and activation of AKT/ERK-associated signaling pathway observed for mammalian P2X7R. Collectively, our results indicate for the first time that both coral and amphioxus P2X7RL as well as flounder P2X7R can interact with eATP, and induce events that trigger mammalian mechanisms, suggesting the high conservation of eATP perception throughout multicellular animal evolution.
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Affiliation(s)
- Huimin Duan
- Institute of Evolution and Marine Biodiversity, Department of Marine Biology, Ocean University of China, Qingdao, 266003, China
| | - Shousheng Ni
- Institute of Evolution and Marine Biodiversity, Department of Marine Biology, Ocean University of China, Qingdao, 266003, China
| | - Shuaiqi Yang
- Institute of Evolution and Marine Biodiversity, Department of Marine Biology, Ocean University of China, Qingdao, 266003, China
| | - Yang Zhou
- Institute of Evolution and Marine Biodiversity, Department of Marine Biology, Ocean University of China, Qingdao, 266003, China
| | - Yu Zhang
- Institute of Evolution and Marine Biodiversity, Department of Marine Biology, Ocean University of China, Qingdao, 266003, China.
| | - Shicui Zhang
- Institute of Evolution and Marine Biodiversity, Department of Marine Biology, Ocean University of China, Qingdao, 266003, China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266003, China.
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9
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Sophocleous RA, Sluyter V, Curtis BL, Curtis SJ, Jurak LM, Faulks M, Spildrejorde M, Gates S, Proctor EJ, Seavers A, Watson D, Kuit T, Dowton M, Stokes L, Sluyter R. Association of a P2RX7 gene missense variant with brachycephalic dog breeds. Anim Genet 2019; 51:127-131. [PMID: 31774195 DOI: 10.1111/age.12884] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/06/2019] [Indexed: 12/16/2022]
Abstract
Missense variants are associated with various phenotypic traits and disorders in dogs. The canine P2RX7 gene, coding the ATP-gated P2X7 receptor ion channel, contains four known missense variants. The current study aimed to examine the presence of these variants in a random sample of pedigree and mixed-pedigree dogs. Exons 3, 8, 11 and 13 of the P2RX7 gene, encoding these four respective variants, in 65 dogs were assessed by Sanger sequencing and combined with existing sequencing data from another 69 dogs. The distribution of these variants was then evaluated in all 134 dogs combined and separately within individual breeds including 35 different pure breeds. The rs23314713 (p.Phe103Leu) and rs23315462 (p.Pro452Ser) variants were present in 47 and 40% of all dogs studied respectively, with the rs23314713 variant associated with brachycephalic breeds. Among pedigree dogs, the rs23314713 and rs23315462 variants were associated with brachycephalic and non-brachycephalic breeds respectively. The rs851148233 (p.Arg270Cys) and rs850760787 (p.Arg365Gln) variants were present only in dogs of Cocker Spaniel and Labrador Retriever pedigrees respectively. No other missense variants were found in exons 3, 8, 11 and 13 of the P2RX7 gene within the dogs. In conclusion, the rs23314713 and rs23315462 missense variants of the P2RX7 gene are present in a large proportion of dogs, with the rs23314713 variant associated with a number of brachycephalic breeds. However, the association of this variant with dogs of bulldog ancestry, not brachycephaly per se, cannot be excluded.
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Affiliation(s)
- R A Sophocleous
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia.,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - V Sluyter
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia.,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - B L Curtis
- Albion Park Veterinary Hospital, Albion Park, NSW, 2527, Australia
| | - S J Curtis
- Albion Park Veterinary Hospital, Albion Park, NSW, 2527, Australia
| | - L M Jurak
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia.,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - M Faulks
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia.,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - M Spildrejorde
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia.,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - S Gates
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia.,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - E-J Proctor
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia.,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - A Seavers
- Oak Flats Veterinary Clinic, Oak Flats, NSW, 2529, Australia
| | - D Watson
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia.,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - T Kuit
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - M Dowton
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia.,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - L Stokes
- School of Pharmacy, University of East Anglia, Norwich, NR4 7TJ, UK
| | - R Sluyter
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia.,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia
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Wei L, Syed Mortadza SA, Yan J, Zhang L, Wang L, Yin Y, Li C, Chalon S, Emond P, Belzung C, Li D, Lu C, Roger S, Jiang LH. ATP-activated P2X7 receptor in the pathophysiology of mood disorders and as an emerging target for the development of novel antidepressant therapeutics. Neurosci Biobehav Rev 2018; 87:192-205. [PMID: 29453990 DOI: 10.1016/j.neubiorev.2018.02.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 02/01/2018] [Accepted: 02/08/2018] [Indexed: 12/11/2022]
Abstract
Mood disorders are a group of psychiatric conditions that represent leading global disease burdens. Increasing evidence from clinical and preclinical studies supports that innate immune system dysfunction plays an important part in the pathophysiology of mood disorders. P2X7 receptor, belonging to the ligand-gated ion channel P2X subfamily of purinergic P2 receptors for extracellular ATP, is highly expressed in immune cells including microglia in the central nervous system (CNS) and has a vital role in mediating innate immune response. The P2X7 receptor is also important in neuron-glia signalling in the CNS. The gene encoding human P2X7 receptor is located in a locus of susceptibility to mood disorders. In this review, we will discuss the recent progress in understanding the role of the P2X7 receptor in the pathogenesis and development of mood disorders and in discovering CNS-penetrable P2X7 antagonists for potential uses in in vivo imaging to monitor brain inflammation and antidepressant therapeutics.
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Affiliation(s)
- Linyu Wei
- Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Xinxiang Medical University, China; School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, United Kingdom
| | - Sharifah A Syed Mortadza
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, United Kingdom; Faculty of Medicine and Health Science, University Putra Malaysia, Selangor, Malaysia
| | - Jing Yan
- Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Xinxiang Medical University, China
| | - Libin Zhang
- Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Xinxiang Medical University, China
| | - Lu Wang
- Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Xinxiang Medical University, China
| | - Yaling Yin
- Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Xinxiang Medical University, China
| | - Chaokun Li
- Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Xinxiang Medical University, China
| | - Sylvie Chalon
- Inserm UMR 1253, iBrain, Université de Tours, Tours, France
| | - Patrick Emond
- Inserm UMR 1253, iBrain, Université de Tours, Tours, France; CHRU de Tours, Service de Médecine Nucléaire In Vitro, Tours, France
| | | | - Dongliang Li
- Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Xinxiang Medical University, China; Key Laboratory for the Brain Research of Henan Province, Xinxiang Medical University, China
| | - Chengbiao Lu
- Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Xinxiang Medical University, China; Key Laboratory for the Brain Research of Henan Province, Xinxiang Medical University, China
| | - Sebastien Roger
- Inserm UMR1069, Nutrition, Croissance et Cancer, Université de Tours, France; Institut Universitaire de France, Paris Cedex 05, France
| | - Lin-Hua Jiang
- Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Xinxiang Medical University, China; School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, United Kingdom; Institut Universitaire de France, Paris Cedex 05, France.
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Bartlett R, Stokes L, Curtis SJ, Curtis BL, Sluyter R. Probenecid directly impairs activation of the canine P2X7 receptor. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2017; 36:736-744. [PMID: 29200326 DOI: 10.1080/15257770.2017.1391395] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The current study aimed to determine if probenecid could directly impair the canine P2X7 receptor, a ligand-gated cation channel activated by extracellular adenosine 5'-triphosphate (ATP). Patch clamp measurements demonstrated that probenecid impairs ATP-induced inward currents in HEK-293 cells expressing canine P2X7. Flow cytometric measurements of ethidium+ uptake into HEK-293 cells expressing canine P2X7 showed that probenecid impairs ATP-induced pore formation in a concentration-dependent manner, with a half maximal inhibitory concentration of 158 µM. Finally, ELISA measurements revealed that probenecid impairs ATP-induced interleukin-1β release in dog blood. In conclusion, this study reveals that probenecid can directly impair canine P2X7 activation.
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Affiliation(s)
- Rachael Bartlett
- a School of Biological Sciences, University of Wollongong , Wollongong , NSW , Australia.,b Centre for Medical and Molecular Bioscience, University of Wollongong , Wollongong , NSW , Australia.,c Illawarra Health and Medical Research Institute , Wollongong , NSW , Australia
| | - Leanne Stokes
- d School of Pharmacy, University of East Anglia , Norwich , United Kingdom
| | - Stephen J Curtis
- e Albion Park Veterinary Hospital , Albion Park , NSW , Australia
| | - Belinda L Curtis
- e Albion Park Veterinary Hospital , Albion Park , NSW , Australia
| | - Ronald Sluyter
- a School of Biological Sciences, University of Wollongong , Wollongong , NSW , Australia.,b Centre for Medical and Molecular Bioscience, University of Wollongong , Wollongong , NSW , Australia.,c Illawarra Health and Medical Research Institute , Wollongong , NSW , Australia
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Abstract
The P2X7 receptor is a trimeric ion channel gated by extracellular adenosine 5'-triphosphate. The receptor is present on an increasing number of different cells types including stem, blood, glial, neural, ocular, bone, dental, exocrine, endothelial, muscle, renal and skin cells. The P2X7 receptor induces various downstream events in a cell-specific manner, including inflammatory molecule release, cell proliferation and death, metabolic events, and phagocytosis. As such this receptor plays important roles in heath and disease. Increasing knowledge about the P2X7 receptor has been gained from studies of, but not limited to, protein chemistry including cloning, site-directed mutagenesis, crystal structures and atomic modeling, as well as from studies of primary tissues and transgenic mice. This chapter focuses on the P2X7 receptor itself. This includes the P2RX7 gene and its products including splice and polymorphic variants. This chapter also reviews modulators of P2X7 receptor activation and inhibition, as well as the transcriptional regulation of the P2RX7 gene via its promoter and enhancer regions, and by microRNA and long-coding RNA. Furthermore, this chapter discusses the post-translational modification of the P2X7 receptor by N-linked glycosylation, adenosine 5'-diphosphate ribosylation and palmitoylation. Finally, this chapter reviews interaction partners of the P2X7 receptor, and its cellular localisation and trafficking within cells.
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Affiliation(s)
- Ronald Sluyter
- School of Biological Sciences, University of Wollongong, Wollongong, NSW, 2522, Australia. .,Centre for Medical and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia. .,Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia.
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Faulks M, Kuit TA, Sophocleous RA, Curtis BL, Curtis SJ, Jurak LM, Sluyter R. P2X7 receptor activation causes phosphatidylserine exposure in canine erythrocytes. World J Hematol 2016; 5:88-93. [DOI: 10.5315/wjh.v5.i4.88] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 08/10/2016] [Accepted: 09/22/2016] [Indexed: 02/05/2023] Open
Abstract
AIM To determine if activation of the ATP-gated P2X7 receptor channel induces phosphatidylserine (PS) exposure in erythrocytes from multiple dog breeds.
METHODS Peripheral blood was collected from 25 dogs representing 13 pedigrees and seven crossbreeds. ATP-induced PS exposure on canine erythrocytes in vitro was assessed using a flow cytometric Annexin V binding assay.
RESULTS ATP induced PS exposure in erythrocytes from all dogs studied. ATP caused PS exposure in a concentration-dependent manner with an EC50 value of 395 μmol/L. The non-P2X7 agonists, ADP or AMP, did not cause PS exposure. The P2X7 antagonist, AZ10606120, but not the P2X1 antagonist, NF449, blocked ATP-induced PS exposure.
CONCLUSION The results indicate that ATP induces PS exposure in erythrocytes from various dog breeds and that this process is mediated by P2X7 activation.
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Bhattacharya A, Biber K. The microglial ATP-gated ion channel P2X7 as a CNS drug target. Glia 2016; 64:1772-87. [PMID: 27219534 DOI: 10.1002/glia.23001] [Citation(s) in RCA: 156] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 04/17/2016] [Accepted: 04/18/2016] [Indexed: 12/14/2022]
Abstract
Based on promising preclinical evidence, microglial P2X7 has increasingly being recognized as a target for therapeutic intervention in neurological and psychiatric diseases. However, despite this knowledge no P2X7-related drug has yet entered clinical trials with respect to CNS diseases. We here discuss the current literature on P2X7 being a drug target and identify unsolved issues and still open questions that have hampered the development of P2X7 dependent therapeutic approaches for CNS diseases. It is concluded here that the lack of brain penetrating P2X7 antagonists is a major obstacle in the field and that central P2X7 is a yet untested clinical drug target. In the CNS, microglial P2X7 activation causes neuroinflammation, which in turn plays a role in various CNS disorders. This has resulted in a surge of brain penetrant P2X7 antagonists. P2X7 is a viable, clinically untested CNS drug target. GLIA 2016;64:1772-1787.
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Affiliation(s)
- Anindya Bhattacharya
- LLC. Neuroscience Drug Discovery, Janssen Research & Development, 3210 Merryfield Row, San Diego, California
| | - Knut Biber
- Department of Psychiatry and Psychotherapy, University Hospital Freiburg, Hauptstrasse 5, Freiburg, Germany.,Department of Neuroscience, University Medical Center Groningen, University of Groningen, Ant. Deusinglaan 1, AV Groningen, The Netherlands
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15
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Bartlett R, Stokes L, Sluyter R. The P2X7 receptor channel: recent developments and the use of P2X7 antagonists in models of disease. Pharmacol Rev 2015; 66:638-75. [PMID: 24928329 DOI: 10.1124/pr.113.008003] [Citation(s) in RCA: 316] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The P2X7 receptor is a trimeric ATP-gated cation channel found predominantly, but not exclusively, on immune cells. P2X7 activation results in a number of downstream events, including the release of proinflammatory mediators and cell death and proliferation. As such, P2X7 plays important roles in various inflammatory, immune, neurologic and musculoskeletal disorders. This review focuses on the use of P2X7 antagonists in rodent models of neurologic disease and injury, inflammation, and musculoskeletal and other disorders. The cloning and characterization of human, rat, mouse, guinea pig, dog, and Rhesus macaque P2X7, as well as recent observations regarding the gating and permeability of P2X7, are discussed. Furthermore, this review discusses polymorphic and splice variants of P2X7, as well as the generation and use of P2X7 knockout mice. Recent evidence for emerging signaling pathways downstream of P2X7 activation and the growing list of negative and positive modulators of P2X7 activation and expression are also described. In addition, the use of P2X7 antagonists in numerous rodent models of disease is extensively summarized. Finally, the use of P2X7 antagonists in clinical trials in humans and future directions exploring P2X7 as a therapeutic target are described.
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Affiliation(s)
- Rachael Bartlett
- School of Biological Sciences, University of Wollongong, New South Wales, Australia and Illawarra Health and Medical Research Institute, Wollongong, New South Wales, Australia (R.B., R.S.); and Health Innovations Research Institute, School of Medical Sciences, RMIT University, Bundoora, Victoria, Australia (L.S.)
| | - Leanne Stokes
- School of Biological Sciences, University of Wollongong, New South Wales, Australia and Illawarra Health and Medical Research Institute, Wollongong, New South Wales, Australia (R.B., R.S.); and Health Innovations Research Institute, School of Medical Sciences, RMIT University, Bundoora, Victoria, Australia (L.S.)
| | - Ronald Sluyter
- School of Biological Sciences, University of Wollongong, New South Wales, Australia and Illawarra Health and Medical Research Institute, Wollongong, New South Wales, Australia (R.B., R.S.); and Health Innovations Research Institute, School of Medical Sciences, RMIT University, Bundoora, Victoria, Australia (L.S.)
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16
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Spildrejorde M, Bartlett R, Stokes L, Jalilian I, Peranec M, Sluyter V, Curtis BL, Skarratt KK, Skora A, Bakhsh T, Seavers A, McArthur JD, Dowton M, Sluyter R. R270C polymorphism leads to loss of function of the canine P2X7 receptor. Physiol Genomics 2014; 46:512-22. [PMID: 24824213 DOI: 10.1152/physiolgenomics.00195.2013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The relative function of the P2X7 receptor, an ATP-gated ion channel, varies between humans due to polymorphisms in the P2RX7 gene. This study aimed to assess the functional impact of P2X7 variation in a random sample of the canine population. Blood and genomic DNA were obtained from 69 dogs selected as representatives of a cross section of different breeds. P2X7 function was determined by flow cytometric measurements of dye uptake and patch-clamp measurements of inward currents. P2X7 expression was determined by immunoblotting and immunocytochemistry. Sequencing was used to identify P2RX7 gene polymorphisms. P2X7 was cloned from an English springer spaniel, and point mutations were introduced into this receptor by site-directed mutagenesis. The relative function of P2X7 on monocytes varied between individual dogs. The canine P2RX7 gene encoded four missense polymorphisms: F103L and P452S, found in heterozygous and homozygous dosage, and R270C and R365Q, found only in heterozygous dosage. Moreover, R270C and R365Q were associated with the cocker spaniel and Labrador retriever, respectively. F103L, R270C, and R365Q but not P452S corresponded to decreased P2X7 function in monocytes but did not explain the majority of differences in P2X7 function between dogs, indicating that other factors contribute to this variability. Heterologous expression of site-directed mutants of P2X7 in human embryonic kidney-293 cells indicated that the R270C mutant was nonfunctional, the F103L and R365Q mutants had partly reduced function, and the P452S mutant functioned normally. Taken together, these data highlight that a R270C polymorphism has major functional impact on canine P2X7.
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Affiliation(s)
- Mari Spildrejorde
- School of Biological Sciences, University of Wollongong, Wollongong, Australia; Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Rachael Bartlett
- School of Biological Sciences, University of Wollongong, Wollongong, Australia; Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Leanne Stokes
- Health Innovations Research Institute, School of Medical Sciences, RMIT University, Bundoora, Australia; Sydney Medical School Nepean, University of Sydney, Nepean Hospital, Penrith, Australia
| | - Iman Jalilian
- School of Biological Sciences, University of Wollongong, Wollongong, Australia; Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Michelle Peranec
- School of Biological Sciences, University of Wollongong, Wollongong, Australia; Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Vanessa Sluyter
- School of Biological Sciences, University of Wollongong, Wollongong, Australia; Illawarra Health and Medical Research Institute, Wollongong, Australia
| | | | - Kristen K Skarratt
- Sydney Medical School Nepean, University of Sydney, Nepean Hospital, Penrith, Australia
| | - Amanda Skora
- School of Biological Sciences, University of Wollongong, Wollongong, Australia; Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Tahani Bakhsh
- School of Biological Sciences, University of Wollongong, Wollongong, Australia; Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Aine Seavers
- Oak Flats Veterinary Clinic, Oak Flats, Australia
| | - Jason D McArthur
- School of Biological Sciences, University of Wollongong, Wollongong, Australia; Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Mark Dowton
- School of Biological Sciences, University of Wollongong, Wollongong, Australia; Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Ronald Sluyter
- School of Biological Sciences, University of Wollongong, Wollongong, Australia; Illawarra Health and Medical Research Institute, Wollongong, Australia;
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Spildrejorde M, Curtis SJ, Curtis BL, Sluyter R. Extracellular adenosine 5'-triphosphate and lipopolysaccharide induce interleukin-1β release in canine blood. Vet Immunol Immunopathol 2013; 157:105-10. [PMID: 24290165 DOI: 10.1016/j.vetimm.2013.11.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 10/30/2013] [Accepted: 11/04/2013] [Indexed: 01/12/2023]
Abstract
Binding of extracellular adenosine 5'-triphosphate (ATP) or lipopolysaccharide (LPS) to the damage-associated molecular pattern receptor P2X7 or the pathogen-associated molecular pattern receptor Toll-like receptor (TLR)4, respectively, can induce the release of the pleiotropic cytokine interleukin (IL)-1β in humans and mice. However, the release of IL-1β in dogs remains poorly defined. Using a canine IL-1β enzyme-linked immunosorbent assay, this study investigated whether ATP or LPS could induce IL-1β release in a canine blood-based assay. Short-term incubations (30 min) with ATP induced IL-1β release in LPS-primed canine blood, and this process could be near-completely impaired by the P2X7 antagonist, A438079. In contrast, ATP failed to induce IL-1β release from blood not primed with LPS. ATP-induced IL-1β release was observed with LPS-primed blood from eight different pedigrees or cross breeds. Long-term incubations (24h) with LPS induced IL-1β release in canine blood in a concentration-dependent manner. This process was not altered by co-incubation with A438079. LPS-induced IL-1β release was observed with blood from 10 different pedigrees or cross breeds. These results demonstrate that both extracellular ATP and LPS can induce IL-1β release in dogs, and that ATP- but not LPS-induced IL-1β release in blood is dependent on P2X7 activation. These findings support the role of both P2X7 and TLR4 in IL-1β release in dogs.
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Affiliation(s)
- Mari Spildrejorde
- School of Biological Sciences, University of Wollongong, Wollongong, NSW 2522, Australia; Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Stephen J Curtis
- Albion Park Veterinary Hospital, Albion Park, NSW 2527, Australia
| | - Belinda L Curtis
- Albion Park Veterinary Hospital, Albion Park, NSW 2527, Australia
| | - Ronald Sluyter
- School of Biological Sciences, University of Wollongong, Wollongong, NSW 2522, Australia; Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia.
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Ali Z, Laurijssens B, Ostenfeld T, McHugh S, Stylianou A, Scott-Stevens P, Hosking L, Dewit O, Richardson JC, Chen C. Pharmacokinetic and pharmacodynamic profiling of a P2X7 receptor allosteric modulator GSK1482160 in healthy human subjects. Br J Clin Pharmacol 2013; 75:197-207. [PMID: 22568863 DOI: 10.1111/j.1365-2125.2012.04320.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
AIMS This paper describes findings from the first-in-human study for GSK1482160, an orally available allosteric P2X7 receptor modulator. The study aimed to assess the pharmacokinetics (PK), pharmacodynamics (PD), safety and tolerability of the compound in healthy subjects. METHODS Escalating single doses of up to 1 g were administered to healthy subjects in a single-blind and placebo-controlled fashion. Safety, tolerability, blood drug concentrations and ex vivo Il-1β production in blood were evaluated. RESULTS Drug concentration peaked within 3.5 h of dosing under fasting conditions and declined thereafter with a relatively short half-life of less than 4.5 h. Exposure was proportional to dose with between subject variability of less than 60%. A PK/PD model quantified Il-1β as a function of drug exposure. The model allowed simulation of in vivo pharmacology for various untested dose levels and regimens. Furthermore, the mechanistic model supported the hypothesis that the compound reduces the efficacy of ATP at the P2X7 receptor without affecting its affinity. No major safety or tolerability concerns were identified in this small study (n = 29), except for one case of asymptomatic accelerated idioventricular rhythm at the top dose. CONCLUSION The model-based approach maximized analysis power by integrating all biomarker data and revealed mechanistic insight into the pharmacology of P2X7 modulation by GSK1482160. Simulations by this model ultimately led to the discontinuation of the development of this compound. The therapeutic relevance of the P2X7 receptor remains to be tested in patients. The mechanistic-model-based approach can be applied widely to drug development.
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Jiang LH, Baldwin JM, Roger S, Baldwin SA. Insights into the Molecular Mechanisms Underlying Mammalian P2X7 Receptor Functions and Contributions in Diseases, Revealed by Structural Modeling and Single Nucleotide Polymorphisms. Front Pharmacol 2013; 4:55. [PMID: 23675347 PMCID: PMC3646254 DOI: 10.3389/fphar.2013.00055] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 04/11/2013] [Indexed: 12/13/2022] Open
Abstract
The mammalian P2X7 receptors (P2X7Rs), a member of the ionotropic P2X receptor family with distinctive functional properties, play an important part in mediating extracellular ATP signaling in health and disease. A clear delineation of the molecular mechanisms underlying the key receptor properties, such as ATP-binding, ion permeation, and large pore formation of the mammalian P2X7Rs, is still lacking, but such knowledge is crucial for a better understanding of their physiological functions and contributions in diseases and for development of therapeutics. The recent breakthroughs in determining the atomic structures of the zebrafish P2X4.1R in the closed and ATP-bound open states have provided the long-awaited structural information. The human P2RX7 gene is abundant with non-synonymous single nucleotide polymorphisms (NS-SNPs), which generate a repertoire of human P2X7Rs with point mutations. Characterizations of the NS-SNPs identified in patients of various disease conditions and the resulting mutations have informed previously unknown molecular mechanisms determining the mammalian P2X7R functions and diseases. In this review, we will discuss the new insights into such mechanisms provided by structural modeling and recent functional and genetic linkage studies of NS-SNPs.
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Affiliation(s)
- Lin-Hua Jiang
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds Leeds, UK
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Cosentino S, Banfi C, Burbiel JC, Luo H, Tremoli E, Abbracchio MP. Cardiomyocyte death induced by ischaemic/hypoxic stress is differentially affected by distinct purinergic P2 receptors. J Cell Mol Med 2012; 16:1074-84. [PMID: 21762374 PMCID: PMC4365886 DOI: 10.1111/j.1582-4934.2011.01382.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Blood levels of extracellular nucleotides (e.g. ATP) are greatly increased during heart ischaemia, but, despite the presence of their specific receptors on cardiomyocytes (both P2X and P2Y subtypes), their effects on the subsequent myocardial damage are still unknown. In this study, we aimed at investigating the role of ATP and specific P2 receptors in the appearance of cell injury in a cardiac model of ischaemic/hypoxic stress. Cells were maintained in a modular incubator chamber in a controlled humidified atmosphere of 95% N2 for 16 hrs in a glucose-free medium. In this condition, we detected an early increase in the release of ATP in the culture medium, which was followed by a massive increase in the release of cytoplasmic histone-associated-DNA-fragments, a marker of apoptosis. Addition of either apyrase, which degrades extracellular ATP, or various inhibitors of ATP release via connexin hemichannels fully abolished ischaemic/hypoxic stress-associated apoptosis. To dissect the role of specific P2 receptor subtypes, we used a combined approach: (i) non-selective and, when available, subtype-selective P2 antagonists, were added to cardiomyocytes before ischaemic/hypoxic stress; (ii) selected P2 receptors genes were silenced via specific small interfering RNAs. Both approaches indicated that the P2Y2 and P2χ7 receptor subtypes are directly involved in the induction of cell death during ischaemic/hypoxic stress, whereas the P2Y4 receptor has a protective effect. Overall, these findings indicate a role for ATP and its receptors in modulating cardiomyocyte damage during ischaemic/hypoxic stress.
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Activation of the damage-associated molecular pattern receptor P2X7 induces interleukin-1β release from canine monocytes. Vet Immunol Immunopathol 2012; 149:86-91. [PMID: 22652409 DOI: 10.1016/j.vetimm.2012.05.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2012] [Revised: 04/27/2012] [Accepted: 05/02/2012] [Indexed: 02/07/2023]
Abstract
P2X7, a damage-associated molecular pattern receptor and adenosine 5'-triphosphate (ATP)-gated cation channel, plays an important role in the activation of the NALP3 inflammasome and subsequent release of interleukin (IL)-1β from human monocytes; however its role in monocytes from other species including the dog remains poorly defined. This study investigated the role of P2X7 in canine monocytes, including its role in IL-1β release. A fixed-time flow cytometric assay demonstrated that activation of P2X7 by extracellular ATP induces the uptake of the organic cation, YO-PRO-1(2+), into peripheral blood monocytes from various dog breeds, a process impaired by the specific P2X7 antagonist, A438079. Moreover, in five different breeds, relative P2X7 function in monocytes was about half that of peripheral blood T cells but similar to that of peripheral blood B cells. Reverse transcription-PCR demonstrated the presence of P2X7, NALP3, caspase-1 and IL-1β in LPS-primed canine monocytes. Immunoblotting confirmed the presence of P2X7 in LPS-primed canine monocytes. Finally, extracellular ATP induced YO-PRO-1(2+) uptake into and IL-1β release from these cells, with both processes impaired by A438079. These results demonstrate that P2X7 activation induces the uptake of organic cations into and the release of IL-1β from canine monocytes. These findings indicate that P2X7 may play an important role in IL-1β-dependent processes in dogs.
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Bradley HJ, Browne LE, Yang W, Jiang LH. Pharmacological properties of the rhesus macaque monkey P2X7 receptor. Br J Pharmacol 2012; 164:743-54. [PMID: 21457228 DOI: 10.1111/j.1476-5381.2011.01399.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND AND PURPOSE The human P2X7 (hP2X7) receptor exhibits striking pharmacological differences from its rodent counterparts, particularly in terms of its antagonist profile. Here, we characterized the functional and pharmacological properties of the rhesus macaque monkey P2X7 (rmP2X7) receptor in comparison with the hP2X7 receptor. EXPERIMENTAL APPROACH The rmP2X7 and hP2X7 receptors were heterologously expressed in HEK293 cells. The receptor surface and total expression levels were examined by biotin-labelling and Western blotting. The functional and pharmacological properties were characterized using patch-clamp recording and single-cell imaging. KEY RESULTS The rmP2X7 receptor showed strong cell surface expression. Both ATP and 2'(3')-O-(4-benzoylbenzoyl) adenosine-5'-triphosphate (BzATP) were full agonists in activating the rmP2X7 receptor; the EC₅₀ values were 802 µM for ATP and 58 µM for BzATP, respectively, in extracellular low divalent cation solution. Prolonged activation of the rmP2X7 receptors induced detectable but low level YO-PRO-1 uptake. KN-62, AZ11645373 and A-438079, three hP2X7 selective antagonists, all potently inhibited the rmP2X7 receptor-mediated currents; the IC₅₀ values were 86, 23 and 297 nM respectively. CONCLUSION AND IMPLICATIONS The rmP2X7 receptor exhibits similar pharmacological properties to the hP2X7 receptor. The rhesus macaque monkey thus may represent a valuable model species in elucidating the mechanisms and pharmacological interventions of hP2X7 receptor-related diseases.
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Affiliation(s)
- Helen J Bradley
- Institute of Membrane and Systems Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
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Michel AD, Ng SW, Roman S, Clay WC, Dean DK, Walter DS. Mechanism of action of species-selective P2X(7) receptor antagonists. Br J Pharmacol 2009; 156:1312-25. [PMID: 19309360 DOI: 10.1111/j.1476-5381.2009.00135.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND AND PURPOSE AZ11645373 and N-{2-methyl-5-[(1R, 5S)-9-oxa-3,7-diazabicyclo[3.3.1]non-3-ylcarbonyl]phenyl}-2-tricyclo[3.3.1.13,7]dec-1-ylacetamide hydrochloride (compound-22) are recently described P2X(7) receptor antagonists. In this study we have further characterized these compounds to determine their mechanism of action and interaction with other species orthologues. EXPERIMENTAL APPROACH Antagonist effects at recombinant and chimeric P2X(7) receptors were assessed by ethidium accumulation and radioligand-binding studies. KEY RESULTS AZ11645373 and compound-22 were confirmed as selective non-competitive antagonists of human or rat P2X(7) receptors respectively. Both compounds were weak antagonists of the mouse and guinea-pig P2X(7) receptors and, for each compound, their potency estimates at human and dog P2X(7) receptors were similar. The potency of compound-22 was moderately temperature-dependent while that of AZ11645373 was not. The antagonist effects of both compounds were slowly reversible and were not prevented by decavanadate, suggesting that they were allosteric antagonists. Indeed, the compounds competed for binding sites labelled by an allosteric radio-labelled P2X(7) receptor antagonist. The species selectivity of AZ11645373, but not compound-22, was influenced by the nature of the amino acid at position 95 of the P2X(7) receptor. N(2)-(3,4-difluorophenyl)-N(1)-[2-methyl-5-(1-piperazinylmethyl)phenyl]glycinamide dihydrochloride, a positive allosteric modulator of the rat receptor, reduced the potency of compound-22 at the rat receptor but had little effect on the actions of AZ11645373. CONCLUSIONS AZ11645373 and compound-22 are allosteric antagonists of human and rat P2X(7) receptors respectively. The differential interaction of the two compounds with the receptor suggests there may be more than one allosteric regulatory site on the P2X(7) receptor at which antagonists can bind and affect receptor function.
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Affiliation(s)
- Anton D Michel
- Neurology Centre of Excellence for Drug Discovery, GlaxoSmithKline Research and Development Limited, New Frontiers Science Park, Essex, UK.
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