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Zhang WJ, Luo HL, Zhu ZM. The role of P2X4 receptors in chronic pain: A potential pharmacological target. Biomed Pharmacother 2020; 129:110447. [PMID: 32887026 DOI: 10.1016/j.biopha.2020.110447] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/04/2020] [Accepted: 06/09/2020] [Indexed: 02/07/2023] Open
Abstract
Chronic pain is a common symptom of most clinical diseases, which seriously affects the psychosomatic health of patients and brings some pain to patients. Due to its pathological mechanism is very complicated and the treatment of chronic pain has always been a difficult problem in clinical. Normally, drugs are usually used to relieve pain, but the analgesic effect is not good, especially for cancer pain patients, the analgesic effect is poor. Therefore, exploring the pathogenesis and treatment of chronic pain has aroused the interest of many researchers. A large number of studies have shown that the role of ATP and P2X4 receptor (P2X4R) play an important role in the pathogenesis of chronic pain. P2X4R is dependent on ATP ligand-gated ion channel receptor, which can be activated by ATP and plays an important role in the information transmission of nerve system and the formation of pain. Therefore, in this paper, we comprehensively described the structure and biological functions of P2X4R, and outlined behavioral evaluation methods of chronic pain models. Moreover, we also explored the inherent relationship between P2X4R and chronic pain, and described the therapeutic effect of P2X4R antagonist on chronic pain, and provided some valuable help for the treatment of chronic pain.
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Affiliation(s)
- Wen-Jun Zhang
- 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.
| | - Zheng-Ming Zhu
- The Second Affiliated Hospital, Nanchang University, Nanchang City, Jiangxi Province, 343000, China.
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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.
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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
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3
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Zhang WJ, Zhu ZM, Liu ZX. The role of P2X4 receptor in neuropathic pain and its pharmacological properties. Pharmacol Res 2020; 158:104875. [PMID: 32407956 DOI: 10.1016/j.phrs.2020.104875] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 03/02/2020] [Accepted: 04/24/2020] [Indexed: 12/21/2022]
Abstract
Neuropathic pain (NPP) is a common symptom of most diseases in clinic, which seriously affects the mental health of patients and brings certain pain to patients. Due to its pathological mechanism is very complicated, and thus, its treatment has been one of the challenges in the field of medicine. Therefore, exploring the pathogenesis and treatment approach of NPP has aroused the interest of many researchers. ATP is an important energy information substance, which participates in the signal transmission in the body. The P2 × 4 receptor (P2 × 4R) is dependent on ATP ligand-gated cationic channel receptor, which can be activated by ATP and plays an important role in the transmission of information in the nervous system and the formation of pain. In this paper, we provide a comprehensive review of the structure and function of the P2 × 4R gene. We also discuss the pathogenesis of NPP and the intrinsic relationship between P2 × 4R and NPP. Moreover, we explore the pharmacological properties of P2 × 4R antagonists or inhibitors used as targeted therapies for NPP.
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Affiliation(s)
- Wen-Jun Zhang
- 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.
| | - Zeng-Xu Liu
- Basic Medicine, Nanchang University, Nanchang City, Jiangxi province, 343000, China
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Abstract
Extracellular ATP-gated P2X receptors are trimeric non-selective cation channels important for many physiological events including immune response and neural transmission. These receptors belong to a unique class of ligand-gated ion channels composed of only six transmembrane helices and a relatively small extracellular domain that harbors three ATP-binding pockets. The crystal structures of P2X receptors, including the recent P2X3 structures representing three different stages of the gating cycle, have provided a compelling structural foundation for understanding how this class of ligand-gated ion channels function. These structures, in combination with numerous functional studies ranging from classic mutagenesis and electrophysiology to modern optogenetic pharmacology, have uncovered unique molecular mechanisms of P2X receptor function. This review article summarizes the current knowledge in P2X receptor activation, especially focusing on the mechanisms underlying ATP-binding, conformational changes in the extracellular domain, and channel gating and desensitization.
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Wang J, Sun LF, Cui WW, Zhao WS, Ma XF, Li B, Liu Y, Yang Y, Hu YM, Huang LD, Cheng XY, Li L, Lu XY, Tian Y, Yu Y. Intersubunit physical couplings fostered by the left flipper domain facilitate channel opening of P2X4 receptors. J Biol Chem 2017; 292:7619-7635. [PMID: 28302727 DOI: 10.1074/jbc.m116.771121] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 03/03/2017] [Indexed: 12/14/2022] Open
Abstract
P2X receptors are ATP-gated trimeric channels with important roles in diverse pathophysiological functions. A detailed understanding of the mechanism underlying the gating process of these receptors is thus fundamentally important and may open new therapeutic avenues. The left flipper (LF) domain of the P2X receptors is a flexible loop structure, and its coordinated motions together with the dorsal fin (DF) domain are crucial for the channel gating of the P2X receptors. However, the mechanism underlying the crucial role of the LF domain in the channel gating remains obscure. Here, we propose that the ATP-induced allosteric changes of the LF domain enable it to foster intersubunit physical couplings among the DF and two lower body domains, which are pivotal for the channel gating of P2X4 receptors. Metadynamics analysis indicated that these newly established intersubunit couplings correlate well with the ATP-bound open state of the receptors. Moreover, weakening or strengthening these physical interactions with engineered intersubunit metal bridges remarkably decreased or increased the open probability of the receptors, respectively. Further disulfide cross-linking and covalent modification confirmed that the intersubunit physical couplings among the DF and two lower body domains fostered by the LF domain at the open state act as an integrated structural element that is stringently required for the channel gating of P2X4 receptors. Our observations provide new mechanistic insights into P2X receptor activation and will stimulate development of new allosteric modulators of P2X receptors.
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Affiliation(s)
- Jin Wang
- From the Department of Pharmacology and Chemical Biology, Institute of Medical Sciences and Hongqiao International Institute of Medicine of Shanghai Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Liang-Fei Sun
- From the Department of Pharmacology and Chemical Biology, Institute of Medical Sciences and Hongqiao International Institute of Medicine of Shanghai Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Wen-Wen Cui
- From the Department of Pharmacology and Chemical Biology, Institute of Medical Sciences and Hongqiao International Institute of Medicine of Shanghai Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Wen-Shan Zhao
- From the Department of Pharmacology and Chemical Biology, Institute of Medical Sciences and Hongqiao International Institute of Medicine of Shanghai Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Xue-Fei Ma
- From the Department of Pharmacology and Chemical Biology, Institute of Medical Sciences and Hongqiao International Institute of Medicine of Shanghai Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.,the College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China, and
| | - Bin Li
- From the Department of Pharmacology and Chemical Biology, Institute of Medical Sciences and Hongqiao International Institute of Medicine of Shanghai Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.,the College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China, and
| | - Yan Liu
- From the Department of Pharmacology and Chemical Biology, Institute of Medical Sciences and Hongqiao International Institute of Medicine of Shanghai Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Yang Yang
- From the Department of Pharmacology and Chemical Biology, Institute of Medical Sciences and Hongqiao International Institute of Medicine of Shanghai Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - You-Min Hu
- From the Department of Pharmacology and Chemical Biology, Institute of Medical Sciences and Hongqiao International Institute of Medicine of Shanghai Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Li-Dong Huang
- From the Department of Pharmacology and Chemical Biology, Institute of Medical Sciences and Hongqiao International Institute of Medicine of Shanghai Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Xiao-Yang Cheng
- From the Department of Pharmacology and Chemical Biology, Institute of Medical Sciences and Hongqiao International Institute of Medicine of Shanghai Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Lingyong Li
- the Department of Anesthesiology and Perioperative Medicine, University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030
| | - Xiang-Yang Lu
- the College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China, and
| | - Yun Tian
- the College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China, and
| | - Ye Yu
- From the Department of Pharmacology and Chemical Biology, Institute of Medical Sciences and Hongqiao International Institute of Medicine of Shanghai Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China, .,the College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China, and
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Insights into the channel gating of P2X receptors from structures, dynamics and small molecules. Acta Pharmacol Sin 2016; 37:44-55. [PMID: 26725734 DOI: 10.1038/aps.2015.127] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 11/02/2015] [Indexed: 12/16/2022] Open
Abstract
P2X receptors, as ATP-gated non-selective trimeric ion channels, are permeable to Na(+), K(+) and Ca(2+). Comparing with other ligand-gated ion channel families, P2X receptors are distinct in their unique gating properties and pathophysiological roles, and have attracted attention as promising drug targets for a variety of diseases, such as neuropathic pain, multiple sclerosis, rheumatoid arthritis and thrombus. Several small molecule inhibitors for distinct P2X subtypes have entered into clinical trials. However, many questions regarding the gating mechanism of P2X remain unsolved. The structural determinations of P2X receptors at the resting and ATP-bound open states revealed that P2X receptor gating is a cooperative allosteric process involving multiple domains, which marks the beginning of the post-structure era of P2X research at atomic level. Here, we review the current knowledge on the structure-function relationship of P2X receptors, depict the whole picture of allosteric changes during the channel gating, and summarize the active sites that may contribute to new strategies for developing novel allosteric drugs targeting P2X receptors.
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Hausmann R, Kless A, Schmalzing G. Key sites for P2X receptor function and multimerization: overview of mutagenesis studies on a structural basis. Curr Med Chem 2015; 22:799-818. [PMID: 25439586 PMCID: PMC4460280 DOI: 10.2174/0929867322666141128163215] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 10/20/2014] [Accepted: 11/27/2014] [Indexed: 02/07/2023]
Abstract
P2X receptors constitute a seven-member family (P2X1-7) of extracellular ATP-gated cation
channels of widespread expression. Because P2X receptors have been implicated in neurological, inflammatory
and cardiovascular diseases, they constitute promising drug targets. Since the first P2X cDNA sequences
became available in 1994, numerous site-directed mutagenesis studies have been conducted to disclose
key sites of P2X receptor function and oligomerization. The publication of the 3-Å crystal structures of the zebrafish
P2X4 (zfP2X4) receptor in the homotrimeric apo-closed and ATP-bound open states in 2009 and 2012, respectively, has
ushered a new era by allowing for the interpretation of the wealth of molecular data in terms of specific three-dimensional
models and by paving the way for designing more-decisive experiments. Thanks to these structures, the last five years
have provided invaluable insight into our understanding of the structure and function of the P2X receptor class of ligandgated
ion channels. In this review, we provide an overview of mutagenesis studies of the pre- and post-crystal structure
eras that identified amino acid residues of key importance for ligand binding, channel gating, ion flow, formation of the
pore and the channel gate, and desensitization. In addition, the sites that are involved in the trimerization of P2X receptors
are reviewed based on mutagenesis studies and interface contacts that were predicted by the zfP2X4 crystal structures.
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Affiliation(s)
| | | | - Gunther Schmalzing
- Department of Molecular Pharmacology, Medical Faculty of the RWTH Aachen University, Wendlingweg 2, D-52074 Aachen, Germany.
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Roles of the lateral fenestration residues of the P2X₄ receptor that contribute to the channel function and the deactivation effect of ivermectin. Purinergic Signal 2015; 11:229-38. [PMID: 25847072 DOI: 10.1007/s11302-015-9448-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 03/18/2015] [Indexed: 10/23/2022] Open
Abstract
P2X receptors are cation-permeable ion channels gated by extracellular adenosine triphosphate (ATP). Available crystallographic data suggest that ATP-binding ectodomain is connected to the transmembrane pore domain by three structurally conserved linker regions, which additionally frame the lateral fenestrations through which permeating ions enter the channel pore. The role of these linker regions in relaying the conformational change evoked by ATP binding of the ectodomain to the pore-forming transmembrane domain has not been investigated systematically. Using P2X4R as our model, we employed alanine and serine replacement mutagenesis to determine how the side chain structure of these linker regions influences gating. The mutants Y54A/S, F198A/S, and W259A/S all trafficked normally to the plasma membrane of transfected HEK293 cells but were poorly responsive to ATP. Nevertheless, the function of the F198A/S mutants could be recovered by pretreatment with the known positive allosteric modulator of P2X4R, ivermectin (IVM), although the IVM sensitivity of this mutant was significantly impaired relative to wild type. The functional mutants Y195A/S, F200A/S, and F330A/S exhibited ATP sensitivities identical to wild type, consistent with these side chains playing no role in ATP binding. However, Y195A/S, F200A/S, and F330A/S all displayed markedly changed sensitivity to the specific effects of IVM on current deactivation, suggesting that these positions influence allosteric modulation of gating. Taken together, our data indicate that conserved amino acids within the regions linking the ectodomain with the pore-forming transmembrane domain meaningfully contribute to signal transduction and channel gating in P2X receptors.
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Burnstock G, Nistri A, Khakh BS, Giniatullin R. ATP-gated P2X receptors in health and disease. Front Cell Neurosci 2014; 8:204. [PMID: 25104924 PMCID: PMC4109572 DOI: 10.3389/fncel.2014.00204] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2014] [Accepted: 07/07/2014] [Indexed: 12/18/2022] Open
Affiliation(s)
- Geoffrey Burnstock
- Division of Biosciences, Autonomic Neuroscience Centre, University College Medical School London, UK ; Department of Pharmacology and Therapeutics, The University of Melbourne Parkville, VIC, Australia
| | - Andrea Nistri
- Neuroscience Department, International School for Advanced Studies (SISSA) Trieste, Italy
| | - Baljit S Khakh
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles Los Angeles, CA, USA
| | - Rashid Giniatullin
- Department Neurobiology, A. I. Virtanen Institute, University of Eastern Finland Kuopio, Finland ; Laboratory of Neurobiology, Department of Physiology, Kazan Federal University Kazan, Russia
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