1
|
Al-Aqtash R, Collier DM. Ionotropic purinergic receptor 7 (P2X7) channel structure and pharmacology provides insight regarding non-nucleotide agonism. Channels (Austin) 2024; 18:2355150. [PMID: 38762911 PMCID: PMC11110710 DOI: 10.1080/19336950.2024.2355150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Accepted: 05/10/2024] [Indexed: 05/21/2024] Open
Abstract
P2X7 is a member of the Ionotropic Purinergic Receptor (P2X) family. The P2X family of receptors is composed of seven (P2X1-7), ligand-gated, nonselective cation channels. Changes in P2X expression have been reported in multiple disease models. P2Xs have large complex extracellular domains that function as receptors for a variety of ligands, including endogenous and synthetic agonists and antagonists. ATP is the canonical agonist. ATP affinity ranges from nanomolar to micromolar for most P2XRs, but P2X7 has uniquely poor ATP affinity. In many physiological settings, it may be difficult to achieve the millimolar extracellular ATP concentrations needed for P2X7 channel activation; however, channel function is implicated in pain sensation, immune cell function, cardiovascular disease, cancer, and osteoporosis. Multiple high-resolution P2X7 structures have been solved in apo-, ATP-, and antagonist-bound states. P2X7 structural data reveal distinct allosteric and orthosteric antagonist-binding sites. Both allosteric and orthosteric P2X7 antagonists are well documented to inhibit ATP-evoked channel current. However, a growing body of evidence supports P2X7 activation by non-nucleotide agonists, including extracellular histone proteins and human cathelicidin-derived peptides (LL-37). Interestingly, P2X7 non-nucleotide agonism is not inhibited by allosteric antagonists, but is inhibited by orthosteric antagonists. Herein, we review P2X7 function with a focus on the efficacy of available pharmacology on P2X7 channel current activation by non-nucleotide agonists in effort to understand agonist/antagonist efficacy, and consider the impact of these data on the current understanding of P2X7 in physiology and disease given these limitations of P2X7-selective antagonists and incomplete knockout mouse models.
Collapse
Affiliation(s)
- Rua’a Al-Aqtash
- Department of Pharmaceutical Sciences, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Daniel M. Collier
- Department of Pharmaceutical Sciences, University of Tennessee Health Science Center, Memphis, TN, USA
| |
Collapse
|
2
|
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.
Collapse
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..
| |
Collapse
|
3
|
Kesavan J, Watters O, de Diego-Garcia L, Méndez AM, Alves M, Dinkel K, Hamacher M, Prehn JHM, Henshall DC, Engel T. Functional expression of the ATP-gated P2X7 receptor in human iPSC-derived astrocytes. Purinergic Signal 2024; 20:303-309. [PMID: 37453017 PMCID: PMC11189378 DOI: 10.1007/s11302-023-09957-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Accepted: 07/04/2023] [Indexed: 07/18/2023] Open
Abstract
Activation of the ATP-gated P2X7 receptor (P2X7R), implicated in numerous diseases of the brain, can trigger diverse responses such as the release of pro-inflammatory cytokines, modulation of neurotransmission, cell proliferation or cell death. However, despite the known species-specific differences in its pharmacological properties, to date, most functional studies on P2X7R responses have been analyzed in cells from rodents or immortalised cell lines. To assess the endogenous and functional expression of P2X7Rs in human astrocytes, we differentiated human-induced pluripotent stem cells (hiPSCs) into GFAP and S100 β-expressing astrocytes. Immunostaining revealed prominent punctate P2X7R staining. P2X7R protein expression was also confirmed by Western blot. Importantly, stimulation with the potent non-selective P2X7R agonist 2',3'-O-(benzoyl-4-benzoyl)-adenosine 5'- triphosphate (BzATP) or endogenous agonist ATP induced robust calcium rises in hiPSC-derived astrocytes which were blocked by the selective P2X7R antagonists AFC-5128 or JNJ-47965567. Our findings provide evidence for the functional expression of P2X7Rs in hiPSC-derived astrocytes and support their in vitro utility in investigating the role of the P2X7R and drug screening in disorders of the central nervous system (CNS).
Collapse
Affiliation(s)
- Jaideep Kesavan
- Department of Physiology & Medical Physics, RCSI University of Medicine & Health Sciences, Dublin, D02 YN77, Ireland
- FutureNeuro, SFI Research Centre for Chronic and Rare Neurological Diseases, RCSI University of Medicine and Health Sciences, Dublin, D02 YN77, Ireland
| | - Orla Watters
- Department of Physiology & Medical Physics, RCSI University of Medicine & Health Sciences, Dublin, D02 YN77, Ireland
- FutureNeuro, SFI Research Centre for Chronic and Rare Neurological Diseases, RCSI University of Medicine and Health Sciences, Dublin, D02 YN77, Ireland
- Department of Science & Computing, SETU Waterford, Cork Rd., Co., Waterford, X91 K0EK, Ireland
| | - Laura de Diego-Garcia
- Department of Physiology & Medical Physics, RCSI University of Medicine & Health Sciences, Dublin, D02 YN77, Ireland
- Department of Optic and Optometry, Faculty of Optics and Optometry, Complutense University of Madrid, Madrid, 28037, Spain
| | - Aida Menéndez Méndez
- Department of Physiology & Medical Physics, RCSI University of Medicine & Health Sciences, Dublin, D02 YN77, Ireland
| | - Mariana Alves
- Department of Physiology & Medical Physics, RCSI University of Medicine & Health Sciences, Dublin, D02 YN77, Ireland
| | - Klaus Dinkel
- Lead Discovery Center GmbH, Otto-Hahn-Straße 15, 44227, Dortmund, Germany
| | - Michael Hamacher
- Affectis Pharmaceuticals AG, Otto-Hahn-Straße 15, 44227, Dortmund, Germany
| | - Jochen H M Prehn
- Department of Physiology & Medical Physics, RCSI University of Medicine & Health Sciences, Dublin, D02 YN77, Ireland
- FutureNeuro, SFI Research Centre for Chronic and Rare Neurological Diseases, RCSI University of Medicine and Health Sciences, Dublin, D02 YN77, Ireland
| | - David C Henshall
- Department of Physiology & Medical Physics, RCSI University of Medicine & Health Sciences, Dublin, D02 YN77, Ireland
- FutureNeuro, SFI Research Centre for Chronic and Rare Neurological Diseases, RCSI University of Medicine and Health Sciences, Dublin, D02 YN77, Ireland
| | - Tobias Engel
- Department of Physiology & Medical Physics, RCSI University of Medicine & Health Sciences, Dublin, D02 YN77, Ireland.
- FutureNeuro, SFI Research Centre for Chronic and Rare Neurological Diseases, RCSI University of Medicine and Health Sciences, Dublin, D02 YN77, Ireland.
| |
Collapse
|
4
|
Xu YS, Xiang J, Lin SJ. Functional role of P2X7 purinergic receptor in cancer and cancer-related pain. Purinergic Signal 2024:10.1007/s11302-024-10019-w. [PMID: 38771429 DOI: 10.1007/s11302-024-10019-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Accepted: 05/08/2024] [Indexed: 05/22/2024] Open
Abstract
Numerous studies have revealed that the ATP-gated ion channel purinergic 2X7 receptor (P2X7R) plays an important role in tumor progression and the pathogenesis of cancer pain. P2X7R requires activation by extracellular ATP to perform its regulatory role functions. During tumor development or cancer-induced pain, ATP is released from tumor cells or other cells in the tumor microenvironment (such as tumor-associated immune cells), which activates P2X7R, opens ion channels on the cell membrane, affects intracellular molecular metabolism, and regulates the activity of tumor cells. Furthermore, peripheral organs and receptors can be damaged during tumor progression, and P2X7R expression in nerve cells (such as microglia) is significantly upregulated, enhancing sensory afferent information, sensitizing the central nervous system, and inducing or exacerbating pain. These findings reveal that the ATP-P2X7R signaling axis plays a key regulatory role in the pathogenesis of tumors and cancer pain and also has a therapeutic role. Accordingly, in this study, we explored the role of P2X7R in tumors and cancer pain, discussed the pharmacological properties of inhibiting P2X7R activity (such as the use of antagonists) or blocking its expression in the treatment of tumor and cancer pain, and provided an important evidence for the treatment of both in the future.
Collapse
Affiliation(s)
- Yong-Sheng Xu
- The Second Affiliated Hospital, Nanchang University, Nanchang City, 343000, Jiangxi Province, China
| | - Jun Xiang
- The Second Affiliated Hospital, Nanchang University, Nanchang City, 343000, Jiangxi Province, China
| | - Si-Jian Lin
- Department of Rehabilitation Medicine, the Second Affiliated Hospital, Nanchang University, Nanchang City, 343000, Jiangxi Province, China.
| |
Collapse
|
5
|
Wang DP, Zhang M, Li M, Yang XN, Li C, Cao P, Zhu MX, Tian Y, Yu Y, Lei YT. Druggable site near the upper vestibule determines the high affinity and P2X3 homotrimer selectivity of sivopixant/S-600918 and its analogue DDTPA. Br J Pharmacol 2024; 181:1203-1220. [PMID: 37921202 DOI: 10.1111/bph.16273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 09/13/2023] [Accepted: 10/14/2023] [Indexed: 11/04/2023] Open
Abstract
BACKGROUND AND PURPOSE The P2X3 receptor, a trimeric ionotropic purinergic receptor, has emerged as a potential therapeutic target for refractory chronic cough (RCC). Nevertheless, gefapixant/AF-219, the only marketed P2X3 receptor antagonist, might lead taste disorders by modulating the human P2X2/3 (hP2X2/3) heterotrimer. Hence, in RCC drug development, compounds exhibiting strong affinity for the hP2X3 homotrimer and a weak affinity for the hP2X2/3 heterotrimer hold promise. An example of such a molecule is sivopixant/S-600918, a clinical Phase II RCC candidate with a reduced incidence of taste disturbance compared to gefapixant. Sivopixant and its analogue, (3-(4-([3-chloro-4-isopropoxyphenyl]amino)-3-(4-methylbenzyl)-2,6-dioxo-3,6-dihydro-1,3,5-triazin-1(2H)-yl)propanoic acid (DDTPA), exhibit both high affinity and high selectivity for hP2X3 homotrimers, compared with hP2X2/3 heterotrimers. The mechanism underlying the druggable site and its high selectivity remains unclear. EXPERIMENTAL APPROACH To analyse mechanisms that distinguish this drug candidate from other inhibitors of the P2X3 receptors we used a combination of chimera construction, site covalent occupation, metadynamics, mutagenesis and whole-cell recording. KEY RESULTS The high affinity and selectivity of sivopixant/DDTPA for hP2X3 receptors was determined by the tri-symmetric site located close to the upper vestibule. Substitution of only four amino acids inside the upper body domain of hP2X2 with those of hP2X3, enabled the hP2X2/3 heterotrimer to exhibit a similar level of apparent affinity for sivopixant/DDTPA as the hP2X3 homotrimer. CONCLUSION AND IMPLICATIONS From the receptor-ligand recognition perspective, we have elucidated the molecular basis of novel RCC clinical candidates' cough-suppressing properties and reduced side effects, offering a promising approach to the discovery of novel drugs that specifically target P2X3 receptors.
Collapse
Affiliation(s)
- Dong-Ping Wang
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, China
- School of Sciences and State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Meng Zhang
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, China
- School of Sciences and State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Ming Li
- School of Sciences and State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Xiao-Na Yang
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, China
- School of Sciences and State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Changzhu Li
- State Key Laboratory of Utilization of Woody Oil Resource, Hunan Academy of Forestry, Changsha, China
| | - Peng Cao
- Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Michael X Zhu
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Yun Tian
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, China
| | - Ye Yu
- School of Sciences and State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Yun-Tao Lei
- School of Sciences and State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| |
Collapse
|
6
|
Zhang GP, Liao JX, Liu YY, Zhu FQ, Huang HJ, Zhang WJ. Ion channel P2X7 receptor in the progression of cancer. Front Oncol 2024; 13:1297775. [PMID: 38273855 PMCID: PMC10808724 DOI: 10.3389/fonc.2023.1297775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 12/12/2023] [Indexed: 01/27/2024] Open
Abstract
P2X7 receptor (P2X7) is a non-selective and ATP-sensitive ligand-gated cation channel. Studies have confirmed that it is expressed in a variety of cells and correlates with their function, frequently in immune cells and tumor cells. We found increased expression of this receptor in many tumor cells, and it has a role in tumor survival and progression. In immune cells, upregulation of the receptor has a double effect on tumor suppression as well as tumor promotion. This review describes the structure of P2X7 and its role in the tumor microenvironment and presents possible mechanisms of P2X7 in tumor invasion and metastasis. Understanding the potential of P2X7 for tumor treatment, we also present several therapeutic agents targeting P2X7 and their mechanisms of action. In conclusion, the study of P2X7 is an important guideline for the use of clinical tumor therapy and may be able to provide a new idea for tumor treatment, but considering the complexity of the biological effects of P2X7, the drugs should be used with caution in clinical practice.
Collapse
Affiliation(s)
- Guang-ping Zhang
- The Second Affiliated Hospital, Nanchang University, Nanchang, Jiangxi, China
- Department of Critical Medicine, Ganzhou people’s Hospital, Ganzhou, Jiangxi, China
| | - Jun-xiang Liao
- The Second Affiliated Hospital, Nanchang University, Nanchang, Jiangxi, China
| | - Yi-yi Liu
- The Second Affiliated Hospital, Nanchang University, Nanchang, Jiangxi, China
| | - Fu-qi Zhu
- The Second Affiliated Hospital, Nanchang University, Nanchang, Jiangxi, China
| | - Hui-jin Huang
- The Second Affiliated Hospital, Nanchang University, Nanchang, Jiangxi, China
| | - Wen-jun Zhang
- Department of Rehabilitation Medicine, the Second Affiliated Hospital, Nanchang University, Nanchang, Jiangxi, China
| |
Collapse
|
7
|
Sivcev S, Kudova E, Zemkova H. Neurosteroids as positive and negative allosteric modulators of ligand-gated ion channels: P2X receptor perspective. Neuropharmacology 2023; 234:109542. [PMID: 37040816 DOI: 10.1016/j.neuropharm.2023.109542] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 03/06/2023] [Accepted: 04/07/2023] [Indexed: 04/13/2023]
Abstract
Neurosteroids are steroids synthesized de novo in the brain from cholesterol in an independent manner from peripheral steroid sources. The term "neuroactive steroid" includes all steroids independent of their origin, and newly synthesized analogs of neurosteroids that modify neuronal activities. In vivo application of neuroactive steroids induces potent anxiolytic, antidepressant, anticonvulsant, sedative, analgesic and amnesic effects, mainly through interaction with the γ-aminobutyric acid type-A receptor (GABAAR). However, neuroactive steroids also act as positive or negative allosteric regulators on several ligand-gated channels including N-methyl-d-aspartate receptors (NMDARs), nicotinic acetylcholine receptors (nAChRs) and ATP-gated purinergic P2X receptors. Seven different P2X subunits (P2X1-7) can assemble to form homotrimeric or heterotrimeric ion channels permeable for monovalent cations and calcium. Among them, P2X2, P2X4, and P2X7 are the most abundant within the brain and can be regulated by neurosteroids. Transmembrane domains are necessary for neurosteroid binding, however, no generic motif of amino acids can accurately predict the neurosteroid binding site for any of the ligand-gated ion channels including P2X. Here, we will review what is currently known about the modulation of rat and human P2X by neuroactive steroids and the possible structural determinants underlying neurosteroid-induced potentiation and inhibition of the P2X2 and P2X4 receptors.
Collapse
Affiliation(s)
- Sonja Sivcev
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic; Faculty of Science, Charles University, Prague, Czech Republic
| | - Eva Kudova
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Hana Zemkova
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic.
| |
Collapse
|
8
|
Cui WW, Wang SY, Zhang YQ, Wang Y, Fan YZ, Guo CR, Li XH, Lei YT, Wang WH, Yang XN, Hattori M, Li CZ, Wang J, Yu Y. P2X3-selective mechanism of Gefapixant, a drug candidate for the treatment of refractory chronic cough. Comput Struct Biotechnol J 2022; 20:1642-1653. [PMID: 35465163 PMCID: PMC9014320 DOI: 10.1016/j.csbj.2022.03.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 03/16/2022] [Accepted: 03/27/2022] [Indexed: 11/25/2022] Open
Abstract
The mechanism by which Gefapixant/AF-219 selectively acts on the P2X3 receptor is unclear. The negative allosteric site of AF-219 at P2X3 is also a potent allosteric site for other P2X subtypes. The selectivity of AF-219 for P2X3 is determined by the accessibility of binding site and the internal shape of this pocket. The finding will provide new perspectives for drug design against P2X3-mediated diseases such as RCC.
Gefapixant/AF-219, a selective inhibitor of the P2X3 receptor, is the first new drug other than dextromethorphan to be approved for the treatment of refractory chronic cough (RCC) in nearly 60 years. To date, seven P2X subtypes (P2X1-7) activated by extracellular ATP have been cloned, and subtype selectivity of P2X inhibitors is a prerequisite for reducing side effects. We previously identified the site and mechanism of action of Gefapixant/AF-219 on the P2X3 receptor, which occupies a pocket consisting of the left flipper (LF) and lower body (LB) domains. However, the mechanism by which AF-219 selectively acts on the P2X3 receptor is unknown. Here, we combined mutagenesis, chimera construction, molecular simulations, covalent occupation and chemical synthesis, and find that the negative allosteric site of AF-219 at P2X3 is also present in other P2X subtypes, at least for P2X1, P2X2 and P2X4. By constructing each chimera of AF-219 sensitive P2X3 and insensitive P2X2 subtypes, the insensitive P2X2 subtype was made to acquire the inhibitory properties of AF-219 and AF-353, an analog of AF-219 with higher affinity. Our results suggest that the selectivity of AF-219/AF-353 for P2X3 over the other P2X subtypes is determined by a combination of the accessibility of P2X3 binding site and the internal shape of this pocket, a finding that could provide new perspectives for drug design against P2X3-mediated diseases such as RCC, idiopathic pulmonary fibrosis, hypertension and overactive bladder disorder.
Collapse
|
9
|
Sheng D, Hattori M. Recent progress in the structural biology of P2X receptors. Proteins 2022; 90:1779-1785. [PMID: 35023590 DOI: 10.1002/prot.26302] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 01/04/2022] [Accepted: 01/11/2022] [Indexed: 12/27/2022]
Abstract
P2X receptors are ATP-gated trimeric nonselective cation channels that are important for various physiological and pathological processes, including synaptic transmission, pain perception, immune regulation, and apoptosis. Accordingly, they attract a wide range of interest as drug targets, such as those for chronic cough, neuropathic pain, and depression. After the zebrafish P2X4 receptor structure was reported in 2009, various other P2X receptor structures have been reported, extending our understanding of the molecular mechanisms of P2X receptors. This review article describes the recent progress on understanding the structures and mechanisms of P2X receptors, especially of the mechanisms underlying ATP binding and conformational changes during the gating cycle. In addition, since several antagonists for different P2X subtypes have entered into clinical trials, this review also summarizes the binding sites and regulatory mechanisms of these antagonists, which may contribute to new strategies of targeting P2X receptors for drug discovery.
Collapse
Affiliation(s)
- Danqi Sheng
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Shanghai Key Laboratory of Bioactive Small Molecules, Department of Physiology and Neurobiology, School of Life Sciences, Fudan University, Shanghai, China
| | - Motoyuki Hattori
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Shanghai Key Laboratory of Bioactive Small Molecules, Department of Physiology and Neurobiology, School of Life Sciences, Fudan University, Shanghai, China
| |
Collapse
|
10
|
Jackson A, Werry EL, O'Brien-Brown J, Schiavini P, Wilkinson S, Wong ECN, McKenzie ADJ, Maximova A, Kassiou M. Pharmacological characterization of a structural hybrid P2X7R antagonist using ATP and LL-37. Eur J Pharmacol 2022; 914:174667. [PMID: 34863711 DOI: 10.1016/j.ejphar.2021.174667] [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: 05/27/2021] [Revised: 11/26/2021] [Accepted: 11/30/2021] [Indexed: 11/03/2022]
Abstract
Antagonists of the P2X7 receptor (P2X7R) have the potential to treat diseases where neuroinflammation is present such as depression, chronic pain and Alzheimer's disease. We recently developed a structural hybrid (C1; 1-((adamantan-1-yl)methyl)-2-cyano-3-(quinolin-5-yl)guanidine) of a purported competitive P2X7R antagonist (C2; 2-cyano-1-((1S)-1-phenylethyl)-3-(quinolin-5-yl)guanidine) and a likely negative allosteric modulator (NAM) of the P2X7R (C3; N-((adamantan-1-yl)methyl)-2-chloro-5-methoxybenzamide). Here we aimed to pharmacologically characterize C1, to gain insights into how select structural components impact antagonist interaction with the P2X7R. A second aim was to examine the role of the peptide LL-37, an apparent activator of the P2X7R, and compare the ability of multiple P2X7R antagonists to block its effects. Compounds 1, 2 and 3 were characterised using washout, Schild and receptor protection studies, all using dye uptake assays in HEK293 cells expressing the P2X7R. LL-37 was examined in the same HEK293 cells and THP-1 monocytes. Compounds 2 and 3 acted as a BzATP-competitive antagonist and NAM of the P2X7R respectively. Compound 1 was a slowly reversible NAM of the P2X7R suggesting the incorporation of an appropriately positioned adamantane promotes binding to the allosteric site of the P2X7R. LL-37 was shown to potentiate the ability of ATP to induce dye uptake at low concentrations (1-3 μg mL-1) or induce dye uptake alone at higher concentrations (10-20 μg mL-1). None of the P2X7R antagonists studied were able to block LL-37-induced dye uptake bringing in to question the ability of current P2X7R antagonists to inhibit the inflammatory action of LL-37 in vivo.
Collapse
Affiliation(s)
- Alexander Jackson
- Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Eryn L Werry
- Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia; Faculty of Science, The University of Sydney, Sydney, NSW, 2006, Australia
| | | | - Paolo Schiavini
- Faculty of Science, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Shane Wilkinson
- Faculty of Science, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Erick C N Wong
- Faculty of Science, The University of Sydney, Sydney, NSW, 2006, Australia
| | - André D J McKenzie
- Faculty of Science, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Alexandra Maximova
- Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Michael Kassiou
- Faculty of Science, The University of Sydney, Sydney, NSW, 2006, Australia.
| |
Collapse
|
11
|
Abstract
The P2X7 receptor has been proposed as a novel drug target for different types of diseases associated with inflammation, including brain diseases, peripheral inflammation, and cancers. Structurally diverse P2X7 receptor antagonists, mainly negative allosteric modulators (NAMs), have been developed in recent years, and several P2X7 receptor antagonists are currently evaluated in clinical trials. The P2X7 receptor requires high micro- to even millimolar ATP concentrations to be activated. Selective agonists for the P2X7 receptor are not available. Positive allosteric modulators (PAMs) have been described, but PAMs with high potency and selectivity are still lacking. This chapter discusses medicinal chemistry approaches toward the development of P2X7 receptor modulators and presents a selection of recommended tool compounds for studying P2X7 receptors in humans and rodents.
Collapse
Affiliation(s)
- Christa E Müller
- Pharmaceutical & Medicinal Chemistry, PharmaCenter Bonn, Pharmaceutical Institute, University of Bonn, Bonn, Germany.
| | - Vigneshwaran Namasivayam
- Pharmaceutical & Medicinal Chemistry, PharmaCenter Bonn, Pharmaceutical Institute, University of Bonn, Bonn, Germany
| |
Collapse
|
12
|
Collado-Díaz V, Martinez-Cuesta MÁ, Blanch-Ruiz MA, Sánchez-López A, García-Martínez P, Peris JE, Usach I, Ivorra MD, Lacetera A, Martín-Santamaría S, Esplugues JV, Alvarez A. Abacavir Increases Purinergic P2X7 Receptor Activation by ATP: Does a Pro-inflammatory Synergism Underlie Its Cardiovascular Toxicity? Front Pharmacol 2021; 12:613449. [PMID: 33867979 PMCID: PMC8045785 DOI: 10.3389/fphar.2021.613449] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 02/15/2021] [Indexed: 11/15/2022] Open
Abstract
The cardiovascular toxicity of Abacavir is related to its purinergic structure. Purinergic P2X7-receptors (P2X7R), characterized by activation by high concentrations of ATP and with high plasticity, seem implicated. We appraise the nature of the interplay between Abacavir and P2X7R in generating vascular inflammation. The effects of Abacavir on leukocyte-endothelium interactions were compared with those of its metabolite carbovir triphosphate (CBV-TP) or ATP in the presence of apyrase (ATP-ase) or A804598 (P2X7R-antagonist). CBV-TP and ATP levels were evaluated by HPLC, while binding of Abacavir, CBV-TP and ATP to P2X7R was assessed by radioligand and docking studies. Hypersensitivity studies explored a potential allosteric action of Abacavir. Clinical concentrations of Abacavir (20 µmol/L) induced leukocyte-endothelial cell interactions by specifically activating P2X7R, but the drug did not show affinity for the P2X7R ATP-binding site (site 1). CBV-TP levels were undetectable in Abacavir-treated cells, while those of ATP were unaltered. The effects of Abacavir were Apyrase-dependent, implying dependence on endogenous ATP. Exogenous ATP induced a profile of proinflammatory actions similar to Abacavir, but was not entirely P2X7R-dependent. Docking calculations suggested ATP-binding to sites 1 and 2, and Abacavir-binding only to allosteric site 2. A combination of concentrations of Abacavir (1 µmol/L) and ATP (0.1 µmol/L) that had no effect when administered separately induced leukocyte-endothelium interactions mediated by P2X7R and involving Connexin43 channels. Therefore, Abacavir acts as a positive allosteric modulator of P2X7R, turning low concentrations of endogenous ATP themselves incapable of stimulating P2X7R into a functional proinflammatory agonist of the receptor.
Collapse
Affiliation(s)
- Víctor Collado-Díaz
- Departamento de Farmacología, Facultad de Medicina, Universidad de Valencia, Valencia, Spain
| | - Maria Ángeles Martinez-Cuesta
- Departamento de Farmacología, Facultad de Medicina, Universidad de Valencia, Valencia, Spain.,CIBERehd, Valencia, Spain
| | | | - Ainhoa Sánchez-López
- Departamento de Farmacología, Facultad de Medicina, Universidad de Valencia, Valencia, Spain
| | | | - José E Peris
- Departamento de Tecnología Farmacéutica, Facultad de Farmacia, Universidad de Valencia, Valencia, Spain
| | - Iris Usach
- Departamento de Tecnología Farmacéutica, Facultad de Farmacia, Universidad de Valencia, Valencia, Spain
| | - Maria Dolores Ivorra
- Departamento de Farmacología, Facultad de Medicina, Universidad de Valencia, Valencia, Spain
| | - Alessandra Lacetera
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Sonsoles Martín-Santamaría
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Juan V Esplugues
- Departamento de Farmacología, Facultad de Medicina, Universidad de Valencia, Valencia, Spain.,CIBERehd, Valencia, Spain.,FISABIO- Fundación Hospital Universitario Dr. Peset, Valencia, Spain
| | - Angeles Alvarez
- Departamento de Farmacología, Facultad de Medicina, Universidad de Valencia, Valencia, Spain.,CIBERehd, Valencia, Spain
| |
Collapse
|
13
|
Shao X, Guha S, Lu W, Campagno KE, Beckel JM, Mills JA, Yang W, Mitchell CH. Polarized Cytokine Release Triggered by P2X7 Receptor from Retinal Pigmented Epithelial Cells Dependent on Calcium Influx. Cells 2020; 9:cells9122537. [PMID: 33255431 PMCID: PMC7760537 DOI: 10.3390/cells9122537] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 11/13/2020] [Accepted: 11/17/2020] [Indexed: 12/20/2022] Open
Abstract
Cytokine release from non-inflammatory cells is a key step in innate immunity, and agonists triggering cytokine release are central in coordinating responses. P2X7 receptor (P2X7R) stimulation by extracellular ATP is best known to active the NLRP3 inflammasome and release IL-1β, but stimulation also leads to release of other cytokines. As cytokine signaling by retinal pigmented epithelial (RPE) cells is implicated in retinal neurodegeneration, the role of P2X7R in release of cytokine IL-6 from RPE cells was investigated. P2X7R stimulation triggered IL-6 release from primary mouse RPE, human iPS-RPE and human ARPE-19 cells. IL-6 release was polarized, with predominant rise across apical membranes. IL-6 release was inhibited by P2X7R antagonists A438079, A839977, and AZ10606120, but not the NRTI lamivudine (3TC), P2X1R antagonist NF279, or P2Y1R antagonist MRS2179. P2X7R-mediated IL-6 release required extracellular Ca2+ and was blocked by Ca2+ chelator BAPTA. IL-6 release and Ca2+ elevation occurred rapidly, consistent with vesicular IL-6 staining in unstimulated cells. P2X7R stimulation did not trigger IL-1β release in these unprimed cells. P2X7R-mediated IL-6 release was enhanced in RPE cells from the ABCA4−/− mouse model of retinal degeneration. In summary, P2X7R stimulation triggers rapid Ca2+-dependent IL-6 release across the apical membrane of RPE cells.
Collapse
Affiliation(s)
- Xiaolei Shao
- Shenzhen Eye Hospital, School of Optometry, Shenzhen University, Shenzhen 518060, China;
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; (S.G.); (J.M.B.)
| | - Sonia Guha
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; (S.G.); (J.M.B.)
- Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Wennan Lu
- Department of Basic and Translational Science, University of Pennsylvania, Philadelphia, PA 19104, USA; (W.L.); (K.E.C.)
| | - Keith E. Campagno
- Department of Basic and Translational Science, University of Pennsylvania, Philadelphia, PA 19104, USA; (W.L.); (K.E.C.)
| | - Jonathan M. Beckel
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; (S.G.); (J.M.B.)
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Jason A. Mills
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA 19104, USA;
- Kirby Center for Molecular Ophthalmology and Center for Advanced Retinal and Ocular Therapeutics (CAROT), University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Wenli Yang
- Department of Medicine and Institute for Regenerative Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA;
| | - Claire H. Mitchell
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; (S.G.); (J.M.B.)
- Department of Basic and Translational Science, University of Pennsylvania, Philadelphia, PA 19104, USA; (W.L.); (K.E.C.)
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA 19104, USA;
- Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA
- Correspondence: ; Tel.: +1-215-573-2176
| |
Collapse
|
14
|
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.
Collapse
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.)
| |
Collapse
|
15
|
Calzaferri F, Ruiz-Ruiz C, de Diego AMG, de Pascual R, Méndez-López I, Cano-Abad MF, Maneu V, de Los Ríos C, Gandía L, García AG. The purinergic P2X7 receptor as a potential drug target to combat neuroinflammation in neurodegenerative diseases. Med Res Rev 2020; 40:2427-2465. [PMID: 32677086 DOI: 10.1002/med.21710] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 06/22/2020] [Accepted: 06/27/2020] [Indexed: 12/25/2022]
Abstract
Neurodegenerative diseases (NDDs) represent a huge social burden, particularly in Alzheimer's disease (AD) in which all proposed treatments investigated in murine models have failed during clinical trials (CTs). Thus, novel therapeutic strategies remain crucial. Neuroinflammation is a common pathogenic feature of NDDs. As purinergic P2X7 receptors (P2X7Rs) are gatekeepers of inflammation, they could be developed as drug targets for NDDs. Herein, we review this challenging hypothesis and comment on the numerous studies that have investigated P2X7Rs, emphasizing their molecular structure and functions, as well as their role in inflammation. Then, we elaborate on research undertaken in the field of medicinal chemistry to determine potential P2X7R antagonists. Subsequently, we review the state of neuroinflammation and P2X7R expression in the brain, in animal models and patients suffering from AD, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease, multiple sclerosis, and retinal degeneration. Next, we summarize the in vivo studies testing the hypothesis that by mitigating neuroinflammation, P2X7R blockers afford neuroprotection, increasing neuroplasticity and neuronal repair in animal models of NDDs. Finally, we reviewed previous and ongoing CTs investigating compounds directed toward targets associated with NDDs; we propose that CTs with P2X7R antagonists should be initiated. Despite the high expectations for putative P2X7Rs antagonists in various central nervous system diseases, the field is moving forward at a relatively slow pace, presumably due to the complexity of P2X7Rs. A better pharmacological approach to combat NDDs would be a dual strategy, combining P2X7R antagonism with drugs targeting a selective pathway in a given NDD.
Collapse
Affiliation(s)
- Francesco Calzaferri
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Cristina Ruiz-Ruiz
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Antonio M G de Diego
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria, Hospital Universitario de La Princesa, Universidad Autónoma de Madrid, Madrid, Spain
| | - Ricardo de Pascual
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Iago Méndez-López
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - María F Cano-Abad
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria, Hospital Universitario de La Princesa, Universidad Autónoma de Madrid, Madrid, Spain
| | - Victoria Maneu
- Departamento de Óptica, Farmacología y Anatomía, Universidad de Alicante, San Vicente del Raspeig, Spain
| | - Cristóbal de Los Ríos
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria, Hospital Universitario de La Princesa, Universidad Autónoma de Madrid, Madrid, Spain
| | - Luis Gandía
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Antonio G García
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria, Hospital Universitario de La Princesa, Universidad Autónoma de Madrid, Madrid, Spain
| |
Collapse
|
16
|
Lara R, Adinolfi E, Harwood CA, Philpott M, Barden JA, Di Virgilio F, McNulty S. P2X7 in Cancer: From Molecular Mechanisms to Therapeutics. Front Pharmacol 2020; 11:793. [PMID: 32581786 PMCID: PMC7287489 DOI: 10.3389/fphar.2020.00793] [Citation(s) in RCA: 102] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 05/13/2020] [Indexed: 12/18/2022] Open
Abstract
P2X7 is a transmembrane receptor expressed in multiple cell types including neurons, dendritic cells, macrophages, monocytes, B and T cells where it can drive a wide range of physiological responses from pain transduction to immune response. Upon activation by its main ligand, extracellular ATP, P2X7 can form a nonselective channel for cations to enter the cell. Prolonged activation of P2X7, via high levels of extracellular ATP over an extended time period can lead to the formation of a macropore, leading to depolarization of the plasma membrane and ultimately to cell death. Thus, dependent on its activation state, P2X7 can either drive cell survival and proliferation, or induce cell death. In cancer, P2X7 has been shown to have a broad range of functions, including playing key roles in the development and spread of tumor cells. It is therefore unsurprising that P2X7 has been reported to be upregulated in several malignancies. Critically, ATP is present at high extracellular concentrations in the tumor microenvironment (TME) compared to levels observed in normal tissues. These high levels of ATP should present a survival challenge for cancer cells, potentially leading to constitutive receptor activation, prolonged macropore formation and ultimately to cell death. Therefore, to deliver the proven advantages for P2X7 in driving tumor survival and metastatic potential, the P2X7 macropore must be tightly controlled while retaining other functions. Studies have shown that commonly expressed P2X7 splice variants, distinct SNPs and post-translational receptor modifications can impair the capacity of P2X7 to open the macropore. These receptor modifications and potentially others may ultimately protect cancer cells from the negative consequences associated with constitutive activation of P2X7. Significantly, the effects of both P2X7 agonists and antagonists in preclinical tumor models of cancer demonstrate the potential for agents modifying P2X7 function, to provide innovative cancer therapies. This review summarizes recent advances in understanding of the structure and functions of P2X7 and how these impact P2X7 roles in cancer progression. We also review potential therapeutic approaches directed against P2X7.
Collapse
Affiliation(s)
- Romain Lara
- Biosceptre (UK) Limited, Cambridge, United Kingdom
| | - Elena Adinolfi
- Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Catherine A Harwood
- Centre for Cell Biology and Cutaneous Research, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Mike Philpott
- Centre for Cutaneous Research, Blizard Institute, Bart's & The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | | | - Francesco Di Virgilio
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy
| | | |
Collapse
|
17
|
Stokes L, Bidula S, Bibič L, Allum E. To Inhibit or Enhance? Is There a Benefit to Positive Allosteric Modulation of P2X Receptors? Front Pharmacol 2020; 11:627. [PMID: 32477120 PMCID: PMC7235284 DOI: 10.3389/fphar.2020.00627] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 04/21/2020] [Indexed: 12/15/2022] Open
Abstract
The family of ligand-gated ion channels known as P2X receptors were discovered several decades ago. Since the cloning of the seven P2X receptors (P2X1-P2X7), a huge research effort has elucidated their roles in regulating a range of physiological and pathophysiological processes. Transgenic animals have been influential in understanding which P2X receptors could be new therapeutic targets for disease. Furthermore, understanding how inherited mutations can increase susceptibility to disorders and diseases has advanced this knowledge base. There has been an emphasis on the discovery and development of pharmacological tools to help dissect the individual roles of P2X receptors and the pharmaceutical industry has been involved in pushing forward clinical development of several lead compounds. During the discovery phase, a number of positive allosteric modulators have been described for P2X receptors and these have been useful in assigning physiological roles to receptors. This review will consider the major physiological roles of P2X1-P2X7 and discuss whether enhancement of P2X receptor activity would offer any therapeutic benefit. We will review what is known about identified compounds acting as positive allosteric modulators and the recent identification of drug binding pockets for such modulators.
Collapse
Affiliation(s)
- Leanne Stokes
- School of Pharmacy, University of East Anglia, Norwich, United Kingdom
| | - Stefan Bidula
- School of Pharmacy, University of East Anglia, Norwich, United Kingdom
| | - Lučka Bibič
- School of Pharmacy, University of East Anglia, Norwich, United Kingdom
| | - Elizabeth Allum
- School of Pharmacy, University of East Anglia, Norwich, United Kingdom
| |
Collapse
|
18
|
Zhang WJ, Zhu ZM, Liu ZX. The role and pharmacological properties of the P2X7 receptor in neuropathic pain. Brain Res Bull 2020; 155:19-28. [PMID: 31778766 DOI: 10.1016/j.brainresbull.2019.11.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 11/03/2019] [Accepted: 11/11/2019] [Indexed: 02/07/2023]
Abstract
Neuropathic Pain (NPP) is caused by direct or indirect damage to the nervous system and is a common symptom of many diseases. Clinically, drugs are usually used to suppress pain, such as (lidocaine, morphine, etc.), but the effect is short-lived, poor analgesia, and there are certain dependence and side effects. Therefore, the investigation of the treatment of NPP has become an urgent problem in medical, attracting a lot of research attention. P2X7 is dependent on Adenosine triphosphate (ATP) ion channel receptors and has dual functions for the development of nerve damage and pain. In this review, we explored the link between the P2X7 receptor (P2X7R) and NPP, providing insight into the P2X7R and NPP, discussing the pathological mechanism of P2 X7R in NPP and the biological characteristics of P2X7R antagonist inhibiting its over-expression for the targeted therapy of NPP.
Collapse
Affiliation(s)
- Wen-Jun Zhang
- The Second Affiliate Hospital. Nanchang University, Nanchang City. Jiangxi Province, China; Basic Medical School, Nanchang University, Nanchang City, Jiangxi Province, China
| | - Zheng-Ming Zhu
- The Second Affiliate Hospital. Nanchang University, Nanchang City. Jiangxi Province, China.
| | - Zeng-Xu Liu
- Basic Medical School, Nanchang University, Nanchang City, Jiangxi Province, China
| |
Collapse
|
19
|
Zhang WJ, Hu CG, Zhu ZM, Luo HL. Effect of P2X7 receptor on tumorigenesis and its pharmacological properties. Biomed Pharmacother 2020; 125:109844. [PMID: 32004973 DOI: 10.1016/j.biopha.2020.109844] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 12/27/2019] [Accepted: 01/13/2020] [Indexed: 12/20/2022] Open
Abstract
The occurrence and development of tumors is a multi-factor, multi-step, multi-gene pathological process, and its treatment has been the most difficult problem in the field of medicine today. Therefore, exploring the relevant factors involved in the pathogenesis of tumors, improving the diagnostic rate, treatment rate, and prognosis survival rate of tumors have become an urgent problem to be solved. A large number of studies have shown that the P2X7 receptor (P2X7R) and the tumor microenvironment play an important role in regulating the growth, apoptosis, migration and invasion of tumor cells. P2X7R is an ATP ligand-gated cationic channel receptor, which exists in most tissues of the human body. The main function of P2X7R is to regulate the relevant cells (such as macrophages, lymphocytes, and glial cells) to release damaging factors and induce apoptosis and cell death. In recent years, with continuous research and exploration of P2X7R, it has been found that P2X7R exists on the surface of most tumor cells and plays an important role in tumor pathogenesis. The activation of the P2X7R can open the ion channels on the tumor cell membrane (sodium ion, calcium ion influx and potassium ion outflow), trigger rearrangement of the cytoskeleton and changes in membrane fluidity, allow small molecule substances to enter the cell, activate enzymes and kinases in related signaling pathways in cells (such as PKA, PKC, ERK1/2, AKT, and JNK), thereby affecting the development of tumor cells, and can also indirectly affect the growth, apoptosis and migration of tumor cells through tumor microenvironment. At present, P2X7R has been widely recognized for its important role in tumorigenesis and development. In this paper, we give a comprehensive description of the structure and function of the P2X7R gene. We also clarified the concept of tumor microenvironment and its effect on tumors, discussed the relevant pathological mechanisms in the development of tumors, and revealed the intrinsic relationship between P2X7R and tumors. We explored the pharmacological properties of P2X7R antagonists or inhibitors in reducing its expression as targeted therapy for tumors.
Collapse
Affiliation(s)
- Wen-Jun Zhang
- The Second Affiliated Hospital, Nanchang University, Nanchang City, Jiangxi Province, 343000, China
| | - Ce-Gui Hu
- The Second Affiliated Hospital, Nanchang University, Nanchang City, Jiangxi Province, 343000, China
| | - Zheng-Ming Zhu
- The Second Affiliated Hospital, Nanchang University, Nanchang City, Jiangxi Province, 343000, China
| | - Hong-Liang Luo
- The Second Affiliated Hospital, Nanchang University, Nanchang City, Jiangxi Province, 343000, China.
| |
Collapse
|
20
|
Identification of aurintricarboxylic acid as a potent allosteric antagonist of P2X1 and P2X3 receptors. Neuropharmacology 2019; 158:107749. [PMID: 31461640 DOI: 10.1016/j.neuropharm.2019.107749] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 08/14/2019] [Accepted: 08/23/2019] [Indexed: 12/13/2022]
Abstract
The homotrimeric P2X3 receptor, one of the seven members of the ATP-gated P2X receptor family, plays a crucial role in sensory neurotransmission. P2X3 receptor antagonists have been identified as promising drugs to treat chronic cough and are suggested to offer pain relief in chronic pain such as neuropathic pain. Here, we analysed whether compounds affect P2X3 receptor activity by high-throughput screening of the Spectrum Collection of 2000 approved drugs, natural products and bioactive substances. We identified aurintricarboxylic acid (ATA) as a nanomolar-potency antagonist of P2X3 receptor-mediated responses. Two-electrode voltage clamp electrophysiology-based concentration-response analysis and selectivity profiling revealed that ATA strongly inhibits the rP2X1 and rP2X3 receptors (with IC50 values of 8.6 nM and 72.9 nM, respectively) and more weakly inhibits P2X2/3, P2X2, P2X4 or P2X7 receptors (IC50 values of 0.76 μM, 22 μM, 763 μM or 118 μM, respectively). Patch-clamp analysis of mouse DRG neurons revealed that ATA inhibited native P2X3 and P2X2/3 receptors to a similar extent than rat P2X3 and P2X2/3 receptors expressed in Xenopus oocytes. In a radioligand binding assay, up to 30 μM ATA did not compete with [3H]-ATP for rP2X3 receptor binding, indicating a non-competitive mechanism of action. Molecular docking studies, site-directed mutagenesis and concentration-response analysis revealed that ATA binds to the negative allosteric site of the hP2X3 receptor. In summary, ATA as a drug-like pharmacological tool compound is a nanomolar-potency, allosteric antagonist with selectivity towards αβ-methylene-ATP-sensitive P2X1 and P2X3 receptors.
Collapse
|
21
|
Li B, Wang J, Cheng X, Liu Y, Yang Y, Yang X, Guo C, Niu Y, Cao P, Lu X, Zhu MX, Tian Y, Yu Y. Molecular mechanism underlying the subtype-selectivity of competitive inhibitor NF110 and its distinct potencies in human and rat P2X3 receptors. Sci Bull (Beijing) 2018; 63:1616-1625. [PMID: 36658853 DOI: 10.1016/j.scib.2018.11.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 11/08/2018] [Accepted: 11/14/2018] [Indexed: 01/21/2023]
Abstract
P2X receptors are a family of extracellular ATP-gated trimeric cation channels that is widely distributed in human tissues. Quite some drug candidates targeting P2X receptors have entered into preclinical or main phases of clinical trials, but many of them failed due to low subtype-selectivity or species differences in pharmacological activities between human and experimental animals. Here, we identified the distinct inhibitory efficacies of NF110, a competitive inhibitor, between the rat (rP2X3) and human (hP2X3) P2X3 receptors. We demonstrated that this difference is determined by two amino acids located in the dorsal fin (DF) domain of P2X3 receptors. As revealed by mutagenesis, metadynamics, and covalent modification, NF110-mediated rP2X3 inhibition may be through a filling in the cavity formed by the DF, left flipper (LF) and lower body (LB) to partially, rather than fully, occupy the ATP-binding pocket. Moreover, substitution of residues located in the DF and/or LF domains of the rP2X2 receptor, a NF110-insensitive subtype, with the equivalent amino acids of rP2X3, bestowed the sensitivity of rP2X2 to NF110. The critical roles of the DF and LF domains in channel gating of P2X and low conservativity in residue sequences of those two domains raise the possibility that small molecules differentially interacting with the residues of the DF and LF domains of different P2X receptors may modulate channel's activity in a subtype-selective manner. However, the possible species-specificity of P2X inhibitors/modulators makes it more complex when interpreting the preclinical data into clinical researches. Nevertheless, our data provide new insights into the subtype-selectivity of competitive inhibitors and their distinct potencies in the human and experimental animals, both of which are extremely important in the drug discovery of P2X receptors.
Collapse
Affiliation(s)
- Bin Li
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China; Department of Pharmacology and Chemical Biology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Jin Wang
- Department of Pharmacology and Chemical Biology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Xiaoyang Cheng
- Department of Pharmacology and Chemical Biology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Yan Liu
- Department of Pharmacology and Chemical Biology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Yang Yang
- Department of Pharmacology and Chemical Biology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Xiaona Yang
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China; School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Changrun Guo
- School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Youya Niu
- Department of Cell Biology and Genetics, Hunan University of Medicine, Huaihua 418000, China
| | - Peng Cao
- Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Xiangyang Lu
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China
| | - Michael X Zhu
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China; State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmaceutical Science, Guangxi Normal University, Guilin 541004, China
| | - Yun Tian
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China.
| | - Ye Yu
- Department of Pharmacology and Chemical Biology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China; School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing 210009, China.
| |
Collapse
|
22
|
Schmid R, Evans RJ. ATP-Gated P2X Receptor Channels: Molecular Insights into Functional Roles. Annu Rev Physiol 2018; 81:43-62. [PMID: 30354932 DOI: 10.1146/annurev-physiol-020518-114259] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In the nervous system, ATP is co-stored in vesicles with classical transmitters and released in a regulated manner. ATP from the intracellular compartment can also exit the cell through hemichannels and following shear stress or membrane damage. In the past 30 years, the action of ATP as an extracellular transmitter at cell-surface receptors has evolved from somewhat of a novelty that was treated with skepticism to purinergic transmission being accepted as having widespread important functional roles mediated by ATP-gated ionotropic P2X receptors (P2XRs). This review focuses on work published in the last five years and provides an overview of ( a) structural studies, ( b) the molecular basis of channel properties and regulation of P2XRs, and ( c) the physiological and pathophysiological roles of ATP acting at defined P2XR subtypes.
Collapse
Affiliation(s)
- Ralf Schmid
- Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, United Kingdom; .,Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester LE1 7RH, United Kingdom
| | - Richard J Evans
- Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, United Kingdom;
| |
Collapse
|
23
|
Svobodova I, Bhattaracharya A, Ivetic M, Bendova Z, Zemkova H. Circadian ATP Release in Organotypic Cultures of the Rat Suprachiasmatic Nucleus Is Dependent on P2X7 and P2Y Receptors. Front Pharmacol 2018; 9:192. [PMID: 29559915 PMCID: PMC5845546 DOI: 10.3389/fphar.2018.00192] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 02/20/2018] [Indexed: 01/22/2023] Open
Abstract
The circadian rhythms in physiological and behavioral functions are driven by a pacemaker located in the suprachiasmatic nucleus (SCN). The rhythms continue in constant darkness and depend on cell-cell communication between neurons and glia. The SCN astrocytes generate also a circadian rhythm in extracellular adenosine 5′-triphosphate (ATP) accumulation, but molecular mechanisms that regulate ATP release are poorly understood. Here, we tested the hypothesis that ATP is released via the plasma membrane purinergic P2X7 receptors (P2X7Rs) and P2Y receptors (P2YRs) which have been previously shown to be expressed in the SCN tissue at transcriptional level. We have investigated this hypothesis using SCN organotypic cultures, primary cultures of SCN astrocytes, ATP bioluminescent assays, immunohistochemistry, patch-clamping, and calcium imaging. We found that extracellular ATP accumulation in organotypic cultures followed a circadian rhythm, with a peak between 24:00 and 04:00 h, and the trough at ~12:00 h. ATP rhythm was inhibited by application of AZ10606120, A438079, and BBG, specific blockers of P2X7R, and potentiated by GW791343, a positive allosteric modulator of this receptor. Double-immunohistochemical staining revealed high expression of the P2X7R protein in astrocytes of SCN slices. PPADS, a non-specific P2 antagonist, and MRS2179, specific P2Y1R antagonist, also abolished ATP rhythm, whereas the specific P2X4R blocker 5-BDBD was not effective. The pannexin-1 hemichannel blocker carbenoxolone displayed a partial inhibitory effect. The P2Y1R agonist MRS2365, and the P2Y2R agonist MRS2768 potentiated ATP release in organotypic cultures and increase intracellular Ca2+ level in cultured astrocytes. Thus, SCN utilizes multiple purinergic receptor systems and pannexin-1 hemichannels to release ATP.
Collapse
Affiliation(s)
- Irena Svobodova
- Department of Cellular and Molecular Neuroendocrinology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czechia
| | - Anirban Bhattaracharya
- Department of Cellular and Molecular Neuroendocrinology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czechia
| | - Milorad Ivetic
- Department of Cellular and Molecular Neuroendocrinology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czechia
| | - Zdenka Bendova
- Department of Physiology, Faculty of Science, Charles University, Prague, Czechia
| | - Hana Zemkova
- Department of Cellular and Molecular Neuroendocrinology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czechia
| |
Collapse
|
24
|
Gölöncsér F, Baranyi M, Balázsfi D, Demeter K, Haller J, Freund TFF, Zelena D, Sperlágh B. Regulation of Hippocampal 5-HT Release by P2X7 Receptors in Response to Optogenetic Stimulation of Median Raphe Terminals of Mice. Front Mol Neurosci 2017; 10:325. [PMID: 29075178 PMCID: PMC5643475 DOI: 10.3389/fnmol.2017.00325] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 09/27/2017] [Indexed: 01/01/2023] Open
Abstract
Serotonergic and glutamatergic neurons of median raphe region (MRR) play a pivotal role in the modulation of affective and cognitive functions. These neurons synapse both onto themselves and remote cortical areas. P2X7 receptors (P2rx7) are ligand gated ion channels expressed by central presynaptic excitatory nerve terminals and involved in the regulation of neurotransmitter release. P2rx7s are implicated in various neuropsychiatric conditions such as schizophrenia and depression. Here we investigated whether 5-HT release released from the hippocampal terminals of MRR is subject to modulation by P2rx7s. To achieve this goal, an optogenetic approach was used to selectively activate subpopulation of serotonergic terminals derived from the MRR locally, and one of its target area, the hippocampus. Optogenetic activation of neurons in the MRR with 20 Hz was correlated with freezing and enhanced locomotor activity of freely moving mice and elevated extracellular levels of 5-HT, glutamate but not GABA in vivo. Similar optical stimulation (OS) significantly increased [3H]5-HT and [3H]glutamate release in acute MRR and hippocampal slices. We examined spatial and temporal patterns of [3H]5-HT release and the interaction between the serotonin and glutamate systems. Whilst [3H]5-HT release from MRR neurons was [Ca2+]o-dependent and sensitive to TTX, CNQX and DL-AP-5, release from hippocampal terminals was not affected by the latter drugs. Hippocampal [3H]5-HT released by electrical but not OS was subject to modulation by 5- HT1B/D receptors agonist sumatriptan (1 μM), whereas the selective 5-HT1A agonist buspirone (0.1 μM) was without effect. [3H]5-HT released by electrical and optical stimulation was decreased in mice genetically deficient in P2rx7s, and after perfusion with selective P2rx7 antagonists, JNJ-47965567 (0.1 μM), and AZ-10606120 (0.1 μM). Optical and electrical stimulation elevated the extracellular level of ATP. Our results demonstrate for the first time the modulation of 5-HT release from hippocampal MRR terminals by the endogenous activation of P2rx7s. P2rx7 mediated modulation of 5-HT release could contribute to various physiological and pathophysiological phenomena, related to hippocampal serotonergic transmission.
Collapse
Affiliation(s)
- Flóra Gölöncsér
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.,János Szentágothai School of Neurosciences, Semmelweis University School of Ph.D. Studies, Budapest, Hungary
| | - Mária Baranyi
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Diána Balázsfi
- János Szentágothai School of Neurosciences, Semmelweis University School of Ph.D. Studies, Budapest, Hungary.,Laboratory of Stress and Behavior Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Kornél Demeter
- Unit of Behavioral Studies, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - József Haller
- Laboratory of Stress and Behavior Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.,Unit of Behavioral Studies, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Tamás F F Freund
- Laboratory of Cerebral Cortex, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Dóra Zelena
- Laboratory of Stress and Behavior Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Beáta Sperlágh
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| |
Collapse
|
25
|
Neuronal P2X7 Receptor: Involvement in Neuronal Physiology and Pathology. J Neurosci 2017; 37:7063-7072. [PMID: 28747389 DOI: 10.1523/jneurosci.3104-16.2017] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 05/12/2017] [Accepted: 05/16/2017] [Indexed: 12/28/2022] Open
Abstract
The proposed presence of P2X7 receptor (P2X7R) in neurons has been the source of some contention. Initial studies suggested an absence of P2X7R mRNA in neurons, and the apparent nonspecificity of the antibodies used to identify P2X7R raised further doubts. However, subsequent studies using new pharmacological and biomolecular tools provided conclusive evidence supporting the existence of functional P2X7Rs in neurons. The P2X7 receptor has since been shown to play a leading role in multiple aspects of neuronal physiology, including axonal elongation and branching and neurotransmitter release. P2X7R has also been implicated in neuronal pathologies, in which it may influence neuronal survival. Together, this body of research suggests that P2X7R may constitute an important therapeutic target for a variety of neurological disorders.
Collapse
|
26
|
Platania CBM, Giurdanella G, Di Paola L, Leggio GM, Drago F, Salomone S, Bucolo C. P2X7 receptor antagonism: Implications in diabetic retinopathy. Biochem Pharmacol 2017; 138:130-139. [PMID: 28479300 DOI: 10.1016/j.bcp.2017.05.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 05/02/2017] [Indexed: 12/13/2022]
Abstract
Diabetic retinopathy (DR) is the most frequent complication of diabetes and one of leading causes of blindness worldwide. Early phases of DR are characterized by retinal pericyte loss mainly related to concurrent inflammatory process. Recently, an important link between P2X7 receptor (P2X7R) and inflammation has been demonstrated indicating this receptor as potential pharmacological target in DR. Here we first carried out an in silico molecular modeling study in order to characterize the allosteric pocket in P2X7R, and identify a suitable P2X7R antagonist through molecular docking. JNJ47965567 was identified as the hit compound in docking calculations, as well as for its absorption, distribution, metabolism and excretion (ADME) profile. As an in vitro model of early diabetic retinopathy, human retinal pericytes were exposed to high glucose (25mM, 48h) that caused a significant (p<0.05) release of IL-1β and LDH. The block of P2X7R by JNJ47965567 significantly (p<0.05) reverted the damage elicited by high glucose, detected as IL-1β and LDH release. Overall, our findings suggest that the P2X7R represents an attractive pharmacological target to manage the early phase of diabetic retinopathy, and the compound JNJ47965567 is a good template to discover other P2X7R selective antagonists.
Collapse
Affiliation(s)
- Chiara Bianca Maria Platania
- Section of Pharmacology, Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, Catania, Italy
| | - Giovanni Giurdanella
- Section of Pharmacology, Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, Catania, Italy
| | - Luisa Di Paola
- School of Engineering, University Campus BioMedico, Roma, Italy
| | - Gian Marco Leggio
- Section of Pharmacology, Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, Catania, Italy; Center for Research in Ocular Pharmacology - CERFO, University of Catania, Catania, Italy
| | - Filippo Drago
- Section of Pharmacology, Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, Catania, Italy; Center for Research in Ocular Pharmacology - CERFO, University of Catania, Catania, Italy
| | - Salvatore Salomone
- Section of Pharmacology, Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, Catania, Italy; Center for Research in Ocular Pharmacology - CERFO, University of Catania, Catania, Italy
| | - Claudio Bucolo
- Section of Pharmacology, Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, Catania, Italy; Center for Research in Ocular Pharmacology - CERFO, University of Catania, Catania, Italy.
| |
Collapse
|
27
|
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.
Collapse
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.
| |
Collapse
|
28
|
Karasawa A, Kawate T. Structural basis for subtype-specific inhibition of the P2X7 receptor. eLife 2016; 5. [PMID: 27935479 PMCID: PMC5176352 DOI: 10.7554/elife.22153] [Citation(s) in RCA: 187] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 12/08/2016] [Indexed: 12/16/2022] Open
Abstract
The P2X7 receptor is a non-selective cation channel activated by extracellular adenosine triphosphate (ATP). Chronic activation of P2X7 underlies many health problems such as pathologic pain, yet we lack effective antagonists due to poorly understood mechanisms of inhibition. Here we present crystal structures of a mammalian P2X7 receptor complexed with five structurally-unrelated antagonists. Unexpectedly, these drugs all bind to an allosteric site distinct from the ATP-binding pocket in a groove formed between two neighboring subunits. This novel drug-binding pocket accommodates a diversity of small molecules mainly through hydrophobic interactions. Functional assays propose that these compounds allosterically prevent narrowing of the drug-binding pocket and the turret-like architecture during channel opening, which is consistent with a site of action distal to the ATP-binding pocket. These novel mechanistic insights will facilitate the development of P2X7-specific drugs for treating human diseases. DOI:http://dx.doi.org/10.7554/eLife.22153.001
Collapse
Affiliation(s)
- Akira Karasawa
- Department of Molecular Medicine, Cornell University, Ithaca, United States
| | - Toshimitsu Kawate
- Department of Molecular Medicine, Cornell University, Ithaca, United States
| |
Collapse
|
29
|
N-Alkyl-Substituted Isatins Enhance P2X7 Receptor-Induced Interleukin-1β Release from Murine Macrophages. Mediators Inflamm 2016; 2016:2097219. [PMID: 27524862 PMCID: PMC4972911 DOI: 10.1155/2016/2097219] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2016] [Accepted: 06/23/2016] [Indexed: 11/17/2022] Open
Abstract
Extracellular adenosine 5'-triphosphate (ATP) activates the P2X7 receptor channel to induce the rapid release of the proinflammatory cytokine, interleukin- (IL-) 1β, from macrophages. Microtubule rearrangements are thought to be involved in this process. Some isatin derivatives alter microtubules and display anticancer activities. The current study investigated the effect of isatin and seven structurally diverse isatin derivatives on P2X7-mediated IL-1β release from murine J774 macrophages. ATP-induced IL-1β and lactate dehydrogenase (LDH) release were assessed by specific colorimetric assays. P2X7 activity was determined by flow cytometric measurements of ATP-induced cation dye uptake. Cytotoxicity of isatin derivatives was determined using a tetrazolium-based colorimetric assay. ATP caused rapid IL-1β release in a concentration-dependent manner, and this process was completely impaired by the P2X7 antagonist, AZ10606120. In contrast, 5,7-dibromo-N-(p-methoxybenzyl)isatin (NAI) and 3-{4-[5,7-dibromo-1-(4-methoxybenzyl)-2-oxoindolin-3-ylidenamino]phenyl}propanoic acid (NAI-imine) enhanced P2X7-induced IL-1β release by twofold compared to that of isatin and the parent molecule, 5,7-dibromoisatin. NAI and NAI-imine had minimal effect on P2X7-induced dye uptake and LDH release. In contrast, 24-hour incubation with NAI and NAI-imine (in the absence of exogenous ATP) induced macrophage death in a concentration-dependent manner. In conclusion, this study demonstrates that N-alkyl-substituted isatins enhance P2X7 receptor-induced IL-1β release from murine macrophages. Thus, in addition to direct anticancer effects, these compounds may also impact inflammatory and immune cells within the tumor microenvironment.
Collapse
|
30
|
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.
Collapse
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
| |
Collapse
|
31
|
Giannuzzo A, Pedersen SF, Novak I. The P2X7 receptor regulates cell survival, migration and invasion of pancreatic ductal adenocarcinoma cells. Mol Cancer 2015; 14:203. [PMID: 26607222 PMCID: PMC4660609 DOI: 10.1186/s12943-015-0472-4] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 11/18/2015] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Pancreatic ductal adenocarcinoma (PDAC) is presently one of the cancers with the worst survival rates and least effective treatments. Moreover, total deaths due to PDAC are predicted to increase in the next 15 years. Therefore, novel insights into basic mechanism of PDAC development and therapies are needed. PDAC is characterized by a complex microenvironment, in which cancer and stromal cells release different molecules, such as ATP. ATP can be transported and/or exocytosed from active cancer cells and released from dying cells in the necrotic core of the cancer. We hypothesized that one of the ATP receptors, the P2X7 receptor (P2X7R) could be an important player in PDAC behaviour. METHODS We determined the expression (real time PCR and Western blot) and localization (immunofluorescence) of P2X7R in human PDAC cell lines (AsPC-1, BxPC-3, Capan-1, MiaPaCa-2, Panc-1) and a "normal" human pancreatic duct epithelial cell line (HPDE). The function of P2X7R in proliferation (BrdU assay), migration (wound assay) and invasion (Boyden chamber with matrigel) was characterized. Furthermore, we studied P2X7R-dependent pore formation (YoPro-1 assay) and cell death (caspase and annexin V / propidium iodide assays). RESULTS We found higher expression of P2X7R protein in PDAC compared to HPDE cells. P2X7R had notable disparate effects on PDAC survival. Firstly, high concentrations of ATP or the specific P2X7R agonist, BzATP, had cytotoxic effects in all cell lines, and cell death was mediated by necrosis. Moreover, the P2X7R-pore antagonist, A438079, prevented ATP-induced pore formation and cell death. Second, in basal conditions and with low concentrations of ATP/BzATP, the P2X7R allosteric inhibitor AZ10606120 reduced proliferation in all PDAC cell lines. P2X7R also affected other key characteristics of cancer cell behavior. AZ10606120 reduced cell migration and invasion in PDAC cell lines compared to that of untreated/vehicle-treated control cells, and stimulation with sub-millimolar concentrations of ATP or BzATP substantially increased cell invasion. CONCLUSIONS PDAC cell lines overexpress P2X7R and the receptor plays crucial roles in cell survival, migration and invasion. Therefore, we propose that drugs targeting P2X7R could be exploited in therapy of pancreatic cancer.
Collapse
Affiliation(s)
- Andrea Giannuzzo
- Department of Biology, Section of Cell Biology and Physiology, University of Copenhagen, August Krogh Building, Universitetsparken 13, DK-2100, Copenhagen, Denmark.
| | - Stine Falsig Pedersen
- Department of Biology, Section of Cell Biology and Physiology, University of Copenhagen, August Krogh Building, Universitetsparken 13, DK-2100, Copenhagen, Denmark.
| | - Ivana Novak
- Department of Biology, Section of Cell Biology and Physiology, University of Copenhagen, August Krogh Building, Universitetsparken 13, DK-2100, Copenhagen, Denmark.
| |
Collapse
|
32
|
Emerging role of P2X7 receptors in CNS health and disease. Ageing Res Rev 2015; 24:328-42. [PMID: 26478005 DOI: 10.1016/j.arr.2015.10.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Accepted: 10/05/2015] [Indexed: 12/11/2022]
Abstract
Purinergic signalling in the brain is becoming an important focus in the study of CNS health and disease. Various purinergic receptors are found to be present in different brain cells in varying extent, which get activated upon binding of ATP or its analogues. Conventionally, ATP was considered only as a major metabolic fuel of the cell but its recognition as a neurotransmitter in early 1970s, brought meaningful insights in neuron glia crosstalk, participating in various physiological functions in the brain. P2X7R, a member of ligand gated purinergic receptor (P2X) family, is gaining attention in the field of neuroscience because of its emerging role in broad spectrum of ageing and age related neurological disorders. The aim of this review is to provide an overview about the structure and function of P2X7R highlighting its unique features which distinguish it from the other members of its family. This review critically analyzes the literature mentioning the details about the agonist and antagonist of the P2X7R. It also emphasizes the advancements in understanding the dual role of P2X7R in brain development and disorders inviting meaningful insights about its involvement in Alzheimer's disease, Huntington's disease, Multiple Sclerosis, Neuropathic pain, Spinal Cord Injury and NeuroAIDS. Exploring the roles of P2X7R in detail is critical to identify its therapeutic potential in the treatment of acute and chronic neurodegenerative diseases. Moreover, this review also helps to raise more interest in the neurobiology of the purinergic receptors and thus providing new avenues for future research.
Collapse
|
33
|
Sinadinos A, Young CNJ, Al-Khalidi R, Teti A, Kalinski P, Mohamad S, Floriot L, Henry T, Tozzi G, Jiang T, Wurtz O, Lefebvre A, Shugay M, Tong J, Vaudry D, Arkle S, doRego JC, Górecki DC. P2RX7 purinoceptor: a therapeutic target for ameliorating the symptoms of duchenne muscular dystrophy. PLoS Med 2015; 12:e1001888. [PMID: 26461208 PMCID: PMC4604078 DOI: 10.1371/journal.pmed.1001888] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 09/04/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Duchenne muscular dystrophy (DMD) is the most common inherited muscle disease, leading to severe disability and death in young men. Death is caused by the progressive degeneration of striated muscles aggravated by sterile inflammation. The pleiotropic effects of the mutant gene also include cognitive and behavioral impairments and low bone density. Current interventions in DMD are palliative only as no treatment improves the long-term outcome. Therefore, approaches with a translational potential should be investigated, and key abnormalities downstream from the absence of the DMD product, dystrophin, appear to be strong therapeutic targets. We and others have demonstrated that DMD mutations alter ATP signaling and have identified P2RX7 purinoceptor up-regulation as being responsible for the death of muscles in the mdx mouse model of DMD and human DMD lymphoblasts. Moreover, the ATP-P2RX7 axis, being a crucial activator of innate immune responses, can contribute to DMD pathology by stimulating chronic inflammation. We investigated whether ablation of P2RX7 attenuates the DMD model mouse phenotype to assess receptor suitability as a therapeutic target. METHODS AND FINDINGS Using a combination of molecular, histological, and biochemical methods and behavioral analyses in vivo we demonstrate, to our knowledge for the first time, that genetic ablation of P2RX7 in the DMD model mouse produces a widespread functional attenuation of both muscle and non-muscle symptoms. In dystrophic muscles at 4 wk there was an evident recovery in key functional and molecular parameters such as improved muscle structure (minimum Feret diameter, p < 0.001), increased muscle strength in vitro (p < 0.001) and in vivo (p = 0.012), and pro-fibrotic molecular signatures. Serum creatine kinase (CK) levels were lower (p = 0.025), and reduced cognitive impairment (p = 0.006) and bone structure alterations (p < 0.001) were also apparent. Reduction of inflammation and fibrosis persisted at 20 mo in leg (p = 0.038), diaphragm (p = 0.042), and heart muscles (p < 0.001). We show that the amelioration of symptoms was proportional to the extent of receptor depletion and that improvements were observed following administration of two P2RX7 antagonists (CK, p = 0.030 and p = 0.050) without any detectable side effects. However, approaches successful in animal models still need to be proved effective in clinical practice. CONCLUSIONS These results are, to our knowledge, the first to establish that a single treatment can improve muscle function both short and long term and also correct cognitive impairment and bone loss in DMD model mice. The wide-ranging improvements reflect the convergence of P2RX7 ablation on multiple disease mechanisms affecting skeletal and cardiac muscles, inflammatory cells, brain, and bone. Given the impact of P2RX7 blockade in the DMD mouse model, this receptor is an attractive target for translational research: existing drugs with established safety records could potentially be repurposed for treatment of this lethal disease.
Collapse
Affiliation(s)
- Anthony Sinadinos
- Molecular Medicine, School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, United Kingdom
| | - Christopher N. J. Young
- Molecular Medicine, School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, United Kingdom
| | - Rasha Al-Khalidi
- Molecular Medicine, School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, United Kingdom
| | - Anna Teti
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, L’Aquila, Italy
| | - Paweł Kalinski
- Departments of Surgery, Immunology, and Bioengineering, School of Medicine, University of Pittsburgh, Pittsburg, Pennsylvania, United States of America
| | - Shafini Mohamad
- School of Engineering, University of Portsmouth, Portsmouth, United Kingdom
| | - Léonore Floriot
- Platform of Behavioural Analysis (SCAC), University of Rouen, Mont-Saint-Aignan,Rouen, France
| | - Tiphaine Henry
- Platform of Behavioural Analysis (SCAC), University of Rouen, Mont-Saint-Aignan,Rouen, France
| | - Gianluca Tozzi
- School of Engineering, University of Portsmouth, Portsmouth, United Kingdom
| | - Taiwen Jiang
- Molecular Medicine, School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, United Kingdom
| | - Olivier Wurtz
- INSERM U982, Plate-Forme d’Imagerie PRIMACEN, IRIB, University of Rouen, Mont-Saint-Aignan, France
| | - Alexis Lefebvre
- Platform of Behavioural Analysis (SCAC), University of Rouen, Mont-Saint-Aignan,Rouen, France
| | - Mikhail Shugay
- Genomics of Adaptive Immunity Lab, Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry and Pirogov Russian National Research Medical University, Moscow, Russia
| | - Jie Tong
- School of Engineering, University of Portsmouth, Portsmouth, United Kingdom
| | - David Vaudry
- INSERM U982, Plate-Forme d’Imagerie PRIMACEN, IRIB, University of Rouen, Mont-Saint-Aignan, France
| | - Stephen Arkle
- Molecular Medicine, School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, United Kingdom
| | - Jean-Claude doRego
- Platform of Behavioural Analysis (SCAC), University of Rouen, Mont-Saint-Aignan,Rouen, France
- National Center of Scientific Research (CNRS), Caen, France
| | - Dariusz C. Górecki
- Molecular Medicine, School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, United Kingdom
- * E-mail:
| |
Collapse
|
34
|
Paroxetine suppresses recombinant human P2X7 responses. Purinergic Signal 2015; 11:481-90. [PMID: 26341077 DOI: 10.1007/s11302-015-9467-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 08/24/2015] [Indexed: 01/02/2023] Open
Abstract
P2X7 receptor (P2X7) activity may link inflammation to depressive disorders. Genetic variants of human P2X7 have been linked with major depression and bipolar disorders, and the P2X7 knockout mouse has been shown to exhibit anti-depressive-like behaviour. P2X7 is an ATP-gated ion channel and is a major regulator of the pro-inflammatory cytokine interleukin 1β (IL-1β) secretion from monocytes and microglia. We hypothesised that antidepressants may elicit their mood enhancing effects in part via modulating P2X7 activity and reducing inflammatory responses. In this study, we determined whether common psychoactive drugs could affect recombinant and native human P2X7 responses in vitro. Common antidepressants demonstrated opposing effects on human P2X7-mediated responses; paroxetine inhibited while fluoxetine and clomipramine mildly potentiated ATP-induced dye uptake in HEK-293 cells stably expressing recombinant human P2X7. Paroxetine inhibited dye uptake mediated by human P2X7 in a concentration-dependent manner with an IC(50) of 24 μM and significantly reduces ATP-induced inward currents. We confirmed that trifluoperazine hydrochloride suppressed human P2X7 responses (IC(50) of 6.4 μM). Both paroxetine and trifluoperazine did not inhibit rodent P2X7 responses, and mutation of a known residue (F 95L) did not alter the effect of either drug, suggesting neither drug binds at this site. Finally, we demonstrate that P2X7-induced IL-1β secretion from lipopolysaccharide (LPS)-primed human CD14(+) monocytes was suppressed with trifluoperazine and paroxetine.
Collapse
|
35
|
Sophocleous RA, Mullany PRF, Winter KM, Marks DC, Sluyter R. Propensity of red blood cells to undergo P2X7 receptor-mediated phosphatidylserine exposure does not alter during in vivo or ex vivo aging. Transfusion 2015; 55:1946-54. [PMID: 25823581 DOI: 10.1111/trf.13101] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 02/13/2015] [Accepted: 02/13/2015] [Indexed: 12/20/2022]
Abstract
BACKGROUND Phosphatidylserine (PS) exposure facilitates the removal of red blood cells (RBCs) from the circulation, potentially contributing to the loss of stored RBCs after transfusion, as well as senescent RBCs. Activation of the P2X7 receptor by extracellular adenosine 5'-triphosphate (ATP) can induce PS exposure on freshly isolated human RBCs, but whether this process occurs in stored RBCs or changes during RBC aging is unknown. STUDY DESIGN AND METHODS RBCs were processed and stored according to Australian blood banking guidelines. PS exposure was determined by annexin V binding and flow cytometry. Efficacy of P2X antagonists was assessed by flow cytometric measurements of ATP-induced ethidium+ uptake in RPMI 8226 cells. Osmotic fragility was assessed by lysis in hypotonic saline. RBCs were fractionated by discontinuous density centrifugation. RESULTS ATP (1 mmol/L) induced PS exposure on RBCs stored for less than 1 week. This process was near-completely inhibited by the P2X7 antagonists A438079 and AZ10606120 and the P2X1/P2X7 antagonist MRS2159 but not the P2X1 antagonist NF499. ATP-induced PS exposure on RBCs was not dependent on K+, Na+, or Cl- fluxes. ATP did not alter the osmotic fragility of stored RBCs. ATP-induced PS exposure was similar between RBCs of different densities. ATP-induced PS exposure was also similar between RBCs stored for less than 1 week or for 6 weeks. CONCLUSION The propensity of RBCs to undergo P2X7-mediated PS exposure does not alter during in vivo and ex vivo aging. Thus, P2X7 activation is unlikely to be involved in the removal of senescent RBCs or stored RBCs after transfusion.
Collapse
Affiliation(s)
- Reece A Sophocleous
- School of Biological Sciences.,Centre for Medical and Molecular Bioscience, University of Wollongong.,Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia
| | - Phillip R F Mullany
- School of Biological Sciences.,Centre for Medical and Molecular Bioscience, University of Wollongong.,Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia
| | - Kelly M Winter
- Research and Development, Australian Red Cross Blood Service, Sydney, NSW, Australia
| | - Denese C Marks
- Research and Development, Australian Red Cross Blood Service, Sydney, NSW, Australia
| | - Ronald Sluyter
- School of Biological Sciences.,Centre for Medical and Molecular Bioscience, University of Wollongong.,Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia
| |
Collapse
|
36
|
Hara S, Kobayashi M, Kuriiwa F, Mukai T, Mizukami H. Different mechanisms of hydroxyl radical production susceptible to purine P2 receptor antagonists between carbon monoxide poisoning and exogenous ATP in rat striatum. Free Radic Res 2014; 48:1322-33. [PMID: 25096805 DOI: 10.3109/10715762.2014.951842] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Previous studies have suggested that carbon monoxide (CO) poisoning stimulates cAMP production via purine P2Y11-like receptors in the rat striatum, activating cAMP signaling pathways, resulting in hydroxyl radical ((•)OH) production. Extracellular ATP was thought likely to trigger the cascade, but the present study has failed to demonstrate a clear increase in the extracellular ATP due to CO poisoning. The CO-induced (•)OH production was attenuated by the P2Y11 receptor antagonist NF157, in parallel with its abilities to suppress the CO-induced cAMP production. The (•)OH production was more strongly suppressed by a non-selective P2 receptor antagonist, PPADS, which had no effect on cAMP production. More selective antagonists toward the respective P2 receptors susceptible to PPADS, including NF279, had little or no effect on the CO-induced (•)OH production. The intrastriatal administration of exogenous ATP dose-dependently stimulated (•)OH production, which was dose-dependently antagonized by PPADS and NF279 but not by NF157. Exogenous GTP and CTP dose-dependently stimulated (•)OH production, though less potently. The GTP-induced (•)OH production was susceptible to both of NF279 and PPADS, but the CTP-induced (•)OH production was resistant to PPADS. The mechanism of (•)OH production may differ between CO poisoning and exogenous ATP, while multiple P2 receptors could participate in (•)OH production. The CO-induced (•)OH production was susceptible to the inhibition of NADPH oxidase, but not xanthine oxidase. Also, the NADPH oxidase inhibition suppressed (•)OH production induced by forskolin, a stimulator of intracellular cAMP formation. It is likely that (•)OH is produced by NADPH oxidase activation via cAMP signaling pathways during CO poisoning.
Collapse
Affiliation(s)
- S Hara
- Department of Forensic Medicine, Tokyo Medical University , Tokyo , Japan
| | | | | | | | | |
Collapse
|
37
|
Activation of the P2X7 receptor induces the rapid shedding of CD23 from human and murine B cells. Immunol Cell Biol 2014; 93:77-85. [PMID: 25155463 DOI: 10.1038/icb.2014.69] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 06/29/2014] [Accepted: 07/09/2014] [Indexed: 12/22/2022]
Abstract
Activation of the P2X7 receptor by the extracellular damage-associated molecular pattern, adenosine 5'-triphosphate (ATP), induces the shedding of cell surface molecules including the low-affinity IgE receptor, CD23, from human leukocytes. A disintegrin and metalloprotease (ADAM) 10 mediates P2X7-induced shedding of CD23 from multiple myeloma RPMI 8226 B cells; however, whether this process occurs in primary B cells is unknown. The aim of the current study was to determine whether P2X7 activation induces the rapid shedding of CD23 from primary human and murine B cells. Flow cytometric and ELISA measurements showed that ATP treatment of human and murine B cells induced the rapid shedding of CD23. Treatment of cells with the specific P2X7 antagonist, AZ10606120, near-completely impaired ATP-induced CD23 shedding from both human and murine B cells. ATP-induced CD23 shedding was also impaired in B cells from P2X7 knockout mice. The absence of full-length, functional P2X7 in the P2X7 knockout mice was confirmed by immunoblotting of splenic cells, and by flow cytometric measurements of ATP-induced YO-PRO-1(2+) uptake into splenic B and T cells. The broad-spectrum metalloprotease antagonist, BB-94, and the ADAM10 antagonist, GI254023X, impaired P2X7-induced CD23 shedding from both human and murine B cells. These data indicate that P2X7 activation induces the rapid shedding of CD23 from primary human and murine B cells and that this process may be mediated by ADAM10.
Collapse
|
38
|
Stojilkovic SS, Leiva-Salcedo E, Rokic MB, Coddou C. Regulation of ATP-gated P2X channels: from redox signaling to interactions with other proteins. Antioxid Redox Signal 2014; 21:953-70. [PMID: 23944253 PMCID: PMC4116155 DOI: 10.1089/ars.2013.5549] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
SIGNIFICANCE The family of purinergic P2X receptors (P2XRs) is a part of ligand-gated superfamily of channels activated by extracellular adenosine-5'-triphosphate. P2XRs are present in virtually all mammalian tissues as well as in tissues of other vertebrate and nonvertebrate species and mediate a large variety of functions, including fast transmission at central synapses, contraction of smooth muscle cells, platelet aggregation, and macrophage activation to proliferation and cell death. RECENT ADVANCES The recent solving of crystal structure of the zebrafish P2X4.1R is a major advance in the understanding of structural correlates of channel activation and regulation. Combined with growing information obtained in the post-structure era and the reinterpretation of previous work within the context of the tridimensional structure, these data provide a better understanding of how the channel operates at the molecular levels. CRITICAL ISSUES This review focuses on the relationship between redox signaling and P2XR function. We also discuss other allosteric modulation of P2XR gating in the physiological/pathophysiological context. This includes the summary of extracellular actions of trace metals, which can be released to the synaptic cleft, pH decrease that happens during ischemia and inflammation, and calcium, an extracellular and intracellular messenger. FUTURE DIRECTIONS Our evolving understanding of activation and regulation of P2XRs is helpful in clarifying the mechanism by which these channels trigger and modulate cellular functions. Further research is required to identify the signaling pathways contributing to the regulation of the receptor activity and to develop novel and receptor-specific allosteric modulators, which could be used in vivo with therapeutic potential.
Collapse
Affiliation(s)
- Stanko S Stojilkovic
- 1 Section on Cellular Signaling, Program in Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health , Bethesda, Maryland
| | | | | | | |
Collapse
|
39
|
Kaiser M, Sobottka H, Fischer W, Schaefer M, Nörenberg W. Tanshinone II A Sulfonate, but Not Tanshinone II A, Acts as Potent Negative Allosteric Modulator of the Human Purinergic Receptor P2X7. J Pharmacol Exp Ther 2014; 350:531-42. [DOI: 10.1124/jpet.114.214569] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
|
40
|
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.
Collapse
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;
| |
Collapse
|
41
|
Cuadra AE, Custer EE, Bosworth EL, Lemos JR. P2X7 receptors in neurohypophysial terminals: evidence for their role in arginine-vasopressin secretion. J Cell Physiol 2014; 229:333-42. [PMID: 24037803 DOI: 10.1002/jcp.24453] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 08/14/2013] [Indexed: 11/11/2022]
Abstract
Arginine-vasopressin (AVP) plays a major role in maintaining cardiovascular function and related pathologies. The mechanism involved in its release into the circulation is complex and highly regulated. Recent work has implicated the purinergic receptor, P2X7R, in a role for catecholamine-enhanced AVP release in the rat hypothalamic-neurohypophysial (NH) system. However, the site of P2X7R action in this endocrine system, and whether or not it directly mediates release in secretory neurons have not been determined. We hypothesized that the P2X7R is expressed and mediates AVP release in NH terminals. P2X7R function was first examined by patch-clamp recordings in isolated NH terminals. Results revealed that subpopulations of isolated terminals displayed either high ATP-sensitivity or low ATP-sensitivity, the latter of which was characteristic of the rat P2X7R. Additional recordings showed that terminals showing sensitivity to the P2X7R-selective agonist, BzATP, were further inhibited by P2X7R selective antagonists, AZ10606120 and brilliant blue-G. In confocal micrographs from tissue sections and isolated terminals of the NH P2X7R-immunoreactivity was found to be localized in plasma membranes. Lastly, the role of P2X7R on AVP release was tested. Our results showed that BzATP evoked sustained AVP release in NH terminals, which was inhibited by AZ10606120. Taken together, our data lead us to conclude that the P2X7R is expressed in NH terminals and corroborates its role in AVP secretion.
Collapse
Affiliation(s)
- Adolfo E Cuadra
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts
| | | | | | | |
Collapse
|
42
|
Yu Z, Klaasse E, Heitman LH, IJzerman AP. Allosteric modulators of the hERG K+ channel. Toxicol Appl Pharmacol 2014; 274:78-86. [DOI: 10.1016/j.taap.2013.10.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 10/22/2013] [Accepted: 10/25/2013] [Indexed: 11/29/2022]
|
43
|
Fischer W, Urban N, Immig K, Franke H, Schaefer M. Natural compounds with P2X7 receptor-modulating properties. Purinergic Signal 2013; 10:313-26. [PMID: 24163006 PMCID: PMC4040168 DOI: 10.1007/s11302-013-9392-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 10/10/2013] [Indexed: 12/19/2022] Open
Abstract
The adenosine 5'-triphosphate (ATP)-gated P2X7 receptor is a membrane-bound, non-selective cation channel, expressed in a variety of cell types. The P2X7 senses high extracellular ATP concentrations and seems to be implicated in a wide range of cellular functions as well as pathophysiological processes, including immune responses and inflammation, release of gliotransmitters and cytokines, cancer cell growth or development of neurodegenerative diseases. In the present study, we identified natural compounds and analogues that can block or sensitize the ATP (1 mM)-induced Ca(2+) response using a HEK293 cell line stably expressing human P2X7 and fluorometric imaging plate reader technology. For instance, teniposide potently blocked the human P2X7 at sub-miromolar concentrations, but not human P2X4 or rat P2X2. A marked block of ATP-induced Ca(2+) entry and Yo-Pro-1 uptake was also observed in human A375 melanoma cells and mouse microglial cells, both expressing P2X7. On the other hand, agelasine (AGL) and garcinolic acid (GA) facilitated the P2X7 response to ATP in all three cell populations. GA also enhanced the YO-PRO-1 uptake, whereas AGL did not affect the ATP-stimulated intracellular accumulation of this dye. According to the pathophysiological role of P2X7 in various diseases, selective modulators may have potential for further development, e.g. as neuroprotective or antineoplastic drugs.
Collapse
Affiliation(s)
- Wolfgang Fischer
- Rudolf-Boehm-Institute of Pharmacology and Toxicology, University of Leipzig, Haertelstr. 16-18, 04107, Leipzig, Germany,
| | | | | | | | | |
Collapse
|
44
|
Csölle C, Baranyi M, Zsilla G, Kittel A, Gölöncsér F, Illes P, Papp E, Vizi ES, Sperlágh B. Neurochemical Changes in the Mouse Hippocampus Underlying the Antidepressant Effect of Genetic Deletion of P2X7 Receptors. PLoS One 2013; 8:e66547. [PMID: 23805233 PMCID: PMC3689833 DOI: 10.1371/journal.pone.0066547] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Accepted: 05/13/2013] [Indexed: 12/17/2022] Open
Abstract
Recent investigations have revealed that the genetic deletion of P2X7 receptors (P2rx7) results in an antidepressant phenotype in mice. However, the link between the deficiency of P2rx7 and changes in behavior has not yet been explored. In the present study, we studied the effect of genetic deletion of P2rx7 on neurochemical changes in the hippocampus that might underlie the antidepressant phenotype. P2X7 receptor deficient mice (P2rx7−/−) displayed decreased immobility in the tail suspension test (TST) and an attenuated anhedonia response in the sucrose preference test (SPT) following bacterial endotoxin (LPS) challenge. The attenuated anhedonia was reproduced through systemic treatments with P2rx7 antagonists. The activation of P2rx7 resulted in the concentration-dependent release of [3H]glutamate in P2rx7+/+ but not P2rx7−/− mice, and the NR2B subunit mRNA and protein was upregulated in the hippocampus of P2rx7−/− mice. The brain-derived neurotrophic factor (BDNF) expression was higher in saline but not LPS-treated P2rx7−/− mice; the P2rx7 antagonist Brilliant blue G elevated and the P2rx7 agonist benzoylbenzoyl ATP (BzATP) reduced BDNF level. This effect was dependent on the activation of NMDA and non-NMDA receptors but not on Group I metabotropic glutamate receptors (mGluR1,5). An increased 5-bromo-2-deoxyuridine (BrdU) incorporation was also observed in the dentate gyrus derived from P2rx7−/− mice. Basal level of 5-HT was increased, whereas the 5HIAA/5-HT ratio was lower in the hippocampus of P2rx7−/− mice, which accompanied the increased uptake of [3H]5-HT and an elevated number of [3H]citalopram binding sites. The LPS-induced elevation of 5-HT level was absent in P2rx7−/− mice. In conclusion there are several potential mechanisms for the antidepressant phenotype of P2rx7−/− mice, such as the absence of P2rx7-mediated glutamate release, elevated basal BDNF production, enhanced neurogenesis and increased 5-HT bioavailability in the hippocampus.
Collapse
Affiliation(s)
- Cecilia Csölle
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | | | | | | | | | | | | | | | | |
Collapse
|
45
|
CAY10593 inhibits the human P2X7 receptor independently of phospholipase D1 stimulation. Purinergic Signal 2013; 9:609-19. [PMID: 23793974 DOI: 10.1007/s11302-013-9371-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Accepted: 06/09/2013] [Indexed: 10/26/2022] Open
Abstract
The P2X7 receptor is a trimeric ATP-gated cation channel important in health and disease. We have observed that the specific phospholipase D (PLD)1 antagonist, CAY10593 impairs P2X7-induced shedding of the 'low affinity' IgE receptor, CD23. The current study investigated the mode of action of this compound on P2X7 activation. Measurements of ATP-induced ethidium(+) uptake revealed that CAY10593 impaired P2X7-induced pore formation in human RPMI 8226 B cells, P2X7-transfected HEK-293 cells and peripheral blood mononuclear cells. Concentration response curves demonstrated that CAY10593 impaired P2X7-induced pore formation in RPMI 8226 cells more potently than the PLD2 antagonist CAY10594 and the non-specific PLD antagonist halopemide. Electrophysiology measurements demonstrated that CAY10593 also inhibited P2X7-induced inward currents. Notably, RT-PCR demonstrated that PLD1 was absent in RPMI 8226 cells, while choline-Cl medium or 1-butanol, which block PLD stimulation and signalling respectively did not impair P2X7 activation in these cells. This data indicates that CAY10593 impairs human P2X7 independently of PLD1 stimulation and highlights the importance of ensuring that compounds used in signalling studies downstream of P2X7 activation do not affect the receptor itself.
Collapse
|
46
|
Pupovac A, Foster CM, Sluyter R. Human P2X7 receptor activation induces the rapid shedding of CXCL16. Biochem Biophys Res Commun 2013; 432:626-31. [PMID: 23428418 DOI: 10.1016/j.bbrc.2013.01.134] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 01/27/2013] [Indexed: 01/17/2023]
Abstract
Activation of the purinergic P2X7 receptor by extracellular ATP induces the shedding of cell-surface molecules including the low-affinity IgE receptor, CD23 from leukocytes. CD23 is a known substrate of a disintegrin and metalloprotease (ADAM)10. The aim of the current study was to determine if P2X7 activation induced the shedding of the chemokine CXCL16, an ADAM10 substrate. Using immunolabelling and flow cytometry we demonstrate that human RPMI 8226 multiple myeloma B cells, which have been previously shown to express P2X7, also express CXCL16. Flow cytometric and ELISA measurements of ATP-induced loss of cell-surface CXCL16 showed that ATP treatment of RPMI 8226 cells induced the rapid shedding of CXCL16. Treatment of RPMI 8226 cells with the specific P2X7 antagonists, AZ10606120 and KN-62 impaired ATP-induced CXCL16 shedding by ~86% and ~90% respectively. RT-PCR demonstrated that ADAM10 is expressed in these cells and treatment of cells with the ADAM10 inhibitor, GI254023X, impaired ATP-induced CXCL16 shedding by ~87%. GI254023X also impaired P2X7-induced CD23 shedding by ∼57%. This data indicates that human P2X7 activation induces the rapid shedding of CXCL16 and that this process involves ADAM10.
Collapse
Affiliation(s)
- Aleta Pupovac
- School of Biological Sciences, University of Wollongong, Wollongong, NSW, Australia
| | | | | |
Collapse
|
47
|
Xia J, Lim JC, Lu W, Beckel JM, Macarak EJ, Laties AM, Mitchell CH. Neurons respond directly to mechanical deformation with pannexin-mediated ATP release and autostimulation of P2X7 receptors. J Physiol 2012; 590:2285-304. [PMID: 22411013 DOI: 10.1113/jphysiol.2012.227983] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Mechanical deformation produces complex effects on neuronal systems, some of which can lead to dysfunction and neuronal death. While astrocytes are known to respond to mechanical forces, it is not clear whether neurons can also respond directly. We examined mechanosensitive ATP release and the physiological response to this release in isolated retinal ganglion cells. Purified ganglion cells released ATP upon swelling. Release was blocked by carbenoxolone, probenecid or peptide (10)panx, implicating pannexin channels as conduits. Mechanical stretch of retinal ganglion cells also triggered a pannexin-dependent ATP release. Whole cell patch clamp recording demonstrated that mild swelling induced the activation of an Ohmic cation current with linear kinetics. The current was inhibited by removal of extracellular ATP with apyrase, by inhibition of the P2X(7) receptor with A438079, zinc, or AZ 10606120, and by pannexin blockers carbenoxolone and probenecid. Probenecid also inhibited the regulatory volume decrease observed after swelling isolated neurons. Together, these observations indicate mechanical strain triggers ATP release directly from retinal ganglion cells and that this released ATP autostimulates P2X(7) receptors. Since extracellular ATP levels in the retina increase with elevated intraocular pressure, and stimulation of P2X(7) receptors on retinal ganglion cells can be lethal, this autocrine response may impact ganglion cells in glaucoma. It remains to be determined whether the autocrine stimulation of purinergic receptors is a general response to a mechanical deformation in neurons, or whether preventing ATP release through pannexin channels and blocking activation of the P2X(7) receptor, is neuroprotective for stretched neurons.
Collapse
Affiliation(s)
- Jingsheng Xia
- Department of Anatomy and Cell Biology, University of Pennsylvania, 440 Levy Building, 240 S. 40th St, Philadelphia, PA 19104, USA
| | | | | | | | | | | | | |
Collapse
|
48
|
Development of a comprehensive set of P2 receptor pharmacological research compounds. Purinergic Signal 2011; 8:101-12. [PMID: 22052555 DOI: 10.1007/s11302-011-9270-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 09/19/2011] [Indexed: 12/13/2022] Open
Abstract
Pharmacological manipulation of P2X and P2Y receptors has been critical to the elucidation of the biological roles of these receptors within a multitude of physiological and pathological processes. Initial purinergic signalling research made use of compounds based on pyridoxal phosphate, suramin and nucleotide analogues; recently developed compounds are often derivatives of these early tools. Tocris Bioscience first entered the field of purinergic signalling reagents with the commercial release of the pyridoxal phosphate derivative, iso-PPADS. During the past two decades, Tocris has assembled a collection of over 50 compounds for P2 receptor modulation, including research tools commercialised from both academic and industrial laboratories. Recently, a number of P2X subtype-selective compounds have been generated by pharmaceutical company medicinal chemistry programmes, supplementing our range of P2Y-selective compounds. Here, we detail the current, commercially available agonists and antagonists of P2X(1,2/3,3,4,7) and P2Y(1,6,11,12) receptors; considered together, they form the foundations of a comprehensive P2 receptor pharmacological 'toolkit'.
Collapse
|
49
|
|
50
|
Dartt DA, Hodges RR. Interaction of alpha1D-adrenergic and P2X(7) receptors in the rat lacrimal gland and the effect on intracellular [Ca2+] and protein secretion. Invest Ophthalmol Vis Sci 2011; 52:5720-9. [PMID: 21685341 DOI: 10.1167/iovs.11-7358] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
PURPOSE To determine whether α(1D)-adrenergic receptors (α(1D)-AR) and P2X(7) receptors interact by determining their effect on ATP release, intracellular [Ca(2+)] ([Ca(2+)](i)), and protein secretion in rat lacrimal gland acini. METHODS Exorbital lacrimal glands from male Sprague-Dawley rats were divided into pieces or digested with collagenase to form acini. With the use of an imaging system, [Ca(2+)](i) was measured in acini loaded with fura-2. Adenosine triphosphate (ATP) release was determined using the luciferin-luciferase reaction. Peroxidase secretion, our index for protein secretion, was measured spectrophotometrically. Acini were stimulated with the P2X(7) receptor agonist, (benzoylbenzoyl)adenosine 5' triphosphate (BzATP) or the α(1D)-AR agonist phenylephrine with or without antagonist preincubation. RESULTS Phenylephrine increased ATP release from pieces in a time-dependent manner. The α(1D)-AR antagonist BMY7378 blocked the BzATP-stimulated increase in [Ca(2+)](i) but not in peroxidase secretion. The P2X(7) antagonist A438079 blocked the phenylephrine-stimulated increase in [Ca(2+)](i) but not peroxidase secretion. The increase in [Ca(2+)](i) caused by phenylephrine and BzATP used simultaneously or sequentially was additive, as was the increase in peroxidase secretion. The inhibition of protein kinase C isoforms or calcium calmodulin kinase II did not alter the BzATP-induced increase in [Ca(2+)](i). CONCLUSIONS The authors conclude that activation of α(1D)-AR releases ATP, which induces P2X(7) receptors to increase [Ca(2+)](i) but not to stimulate protein secretion. P2X(7) receptors in turn activate α(1D)-AR to increase [Ca(2+)](i) but not to stimulate protein secretion. Furthermore, α(1D)-AR compared with P2X(7) receptors use different cellular mechanisms to increase [Ca(2+)](i) and cause protein secretion.
Collapse
Affiliation(s)
- Darlene A Dartt
- Department of Ophthalmology, Schepens Eye Research Institute, Harvard Medical School, Boston, Massachusetts 02114, USA.
| | | |
Collapse
|