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Sierra-Marquez J, Schaller L, Sassenbach L, Ramírez-Fernández A, Alt P, Rissiek B, Zimmer B, Schredelseker J, Hector J, Stähler T, Koch-Nolte F, Staab-Weijnitz CA, Dietrich A, Kopp R, Nicke A. Different localization of P2X4 and P2X7 receptors in native mouse lung - lack of evidence for a direct P2X4-P2X7 receptor interaction. Front Immunol 2024; 15:1425938. [PMID: 38953020 PMCID: PMC11215518 DOI: 10.3389/fimmu.2024.1425938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Accepted: 05/28/2024] [Indexed: 07/03/2024] Open
Abstract
Introduction P2X receptors are a family of homo- and heterotrimeric cation channels gated by extracellular ATP. The P2X4 and P2X7 subunits show overlapping expression patterns and have been involved in similar physiological processes, such as pain and inflammation as well as various immune cell functions. While formation of P2X2/P2X3 heterotrimers produces a distinct pharmacological phenotype and has been well established, functional identification of a P2X4/P2X7 heteromer has been difficult and evidence for and against a physical association has been found. Most of this evidence stems, however, from in vitro model systems. Methods Here, we used a P2X7-EGFP BAC transgenic mouse model as well as P2X4 and P2X7 knock-out mice to re-investigate a P2X4-P2X7 interaction in mouse lung by biochemical and immunohistochemical experiments as well as quantitative expression analysis. Results No detectable amounts of P2X4 could be co-purified from mouse lung via P2X7-EGFP. In agreement with these findings, immuno-histochemical analysis using a P2X7-specific nanobody revealed only limited overlap in the cellular and subcellular localizations of P2X4 and P2X7 in both the native lung tissue and primary cells. Comparison of P2X4 and P2X7 transcript and protein levels in the respective gene-deficient and wild type mice showed no mutual interrelation between their expression levels in whole lungs. However, a significantly reduced P2rx7 expression was found in alveolar macrophages of P2rx4 -/- mice. Discussion In summary, our detailed analysis of the cellular and subcellular P2X4 and P2X7 localization and expression does not support a physiologically relevant direct association of P2X4 and P2X7 subunits or receptors in vivo.
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Affiliation(s)
- Juan Sierra-Marquez
- Walther Straub Institute of Pharmacology and Toxicology, Member of the German Center for Lung Research (DZL), Faculty of Medicine, LMU Munich, Munich, Germany
| | - Lena Schaller
- Walther Straub Institute of Pharmacology and Toxicology, Member of the German Center for Lung Research (DZL), Faculty of Medicine, LMU Munich, Munich, Germany
| | - Lukas Sassenbach
- Walther Straub Institute of Pharmacology and Toxicology, Member of the German Center for Lung Research (DZL), Faculty of Medicine, LMU Munich, Munich, Germany
| | - Antonio Ramírez-Fernández
- Walther Straub Institute of Pharmacology and Toxicology, Member of the German Center for Lung Research (DZL), Faculty of Medicine, LMU Munich, Munich, Germany
| | - Philipp Alt
- Walther Straub Institute of Pharmacology and Toxicology, Member of the German Center for Lung Research (DZL), Faculty of Medicine, LMU Munich, Munich, Germany
| | - Björn Rissiek
- Department of Neurology, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Béla Zimmer
- Walther Straub Institute of Pharmacology and Toxicology, Member of the German Center for Lung Research (DZL), Faculty of Medicine, LMU Munich, Munich, Germany
| | - Johann Schredelseker
- Walther Straub Institute of Pharmacology and Toxicology, Member of the German Center for Lung Research (DZL), Faculty of Medicine, LMU Munich, Munich, Germany
- Deutsches Zentrum für Herz-Kreislauf-Forschung, Partner Site Munich Heart Alliance, Munich, Germany
| | - Julia Hector
- Walther Straub Institute of Pharmacology and Toxicology, Member of the German Center for Lung Research (DZL), Faculty of Medicine, LMU Munich, Munich, Germany
| | - Tobias Stähler
- Institute of Immunology, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Friedrich Koch-Nolte
- Institute of Immunology, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Claudia A. Staab-Weijnitz
- Institute of Lung Health and Immunity (LHI), Helmholtz Munich, Comprehensive Pneumology Center (CPC-M), Member of the German Center for Lung Research (DZL), Germany
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Alexander Dietrich
- Walther Straub Institute of Pharmacology and Toxicology, Member of the German Center for Lung Research (DZL), Faculty of Medicine, LMU Munich, Munich, Germany
| | - Robin Kopp
- Walther Straub Institute of Pharmacology and Toxicology, Member of the German Center for Lung Research (DZL), Faculty of Medicine, LMU Munich, Munich, Germany
| | - Annette Nicke
- Walther Straub Institute of Pharmacology and Toxicology, Member of the German Center for Lung Research (DZL), Faculty of Medicine, LMU Munich, Munich, Germany
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Biringer RG. Migraine signaling pathways: purine metabolites that regulate migraine and predispose migraineurs to headache. Mol Cell Biochem 2023; 478:2813-2848. [PMID: 36947357 DOI: 10.1007/s11010-023-04701-7] [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: 10/05/2022] [Accepted: 03/06/2023] [Indexed: 03/23/2023]
Abstract
Migraine is a debilitating disorder that afflicts over 1 billion people worldwide, involving attacks that result in a throbbing and pulsating headache. Migraine is thought to be a neurovascular event associated with vasoconstriction, vasodilation, and neuronal activation. Understanding signaling in migraine pathology is central to the development of therapeutics for migraine prophylaxis and for mitigation of migraine in the prodrome phase before pain sets in. The fact that both vasoactivity and neural sensitization are involved in migraine indicates that agonists which promote these phenomena may very well be involved in migraine pathology. One such group of agonists is the purines, in particular, adenosine phosphates and their metabolites. This manuscript explores what is known about the relationship between these metabolites and migraine pathology and explores the potential for such relationships through their known signaling pathways. Reported receptor involvement in vasoaction and nociception.
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Affiliation(s)
- Roger Gregory Biringer
- College of Osteopathic Medicine, Lake Erie College of Osteopathic Medicine, Bradenton, FL, 34211, USA.
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Illes P, Ulrich H, Chen JF, Tang Y. Purinergic receptors in cognitive disturbances. Neurobiol Dis 2023; 185:106229. [PMID: 37453562 DOI: 10.1016/j.nbd.2023.106229] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 07/11/2023] [Accepted: 07/12/2023] [Indexed: 07/18/2023] Open
Abstract
Purinergic receptors (Rs) of the ATP/ADP, UTP/UDP (P2X, P2Y) and adenosine (A1, A2A)-sensitive classes broadly interfere with cognitive processes both under quasi normal and disease conditions. During neurodegenerative illnesses, high concentrations of ATP are released from the damaged neuronal and non-neuronal cells of the brain; then, this ATP is enzymatically degraded to adenosine. Thus, the primary injury in neurodegenerative diseases appears to be caused by various protein aggregates on which a superimposed damage mediated by especially P2X7 and A2AR activation develops; this can be efficiently prevented by small molecular antagonists in animal models of the above diseases, or are mitigated in the respective knockout mice. Dementia is a leading symptom in Alzheimer's disease (AD), and accompanies Parkinson's disease (PD) and Huntington's disease (HD), especially in the advanced states of these illnesses. Animal experimentation suggests that P2X7 and A2ARs are also involved in a number of psychiatric diseases, such as major depressive disorder (MDD), obsessive compulsive behavior, and attention deficit hyperactivity disorder. In conclusion, small molecular antagonists of purinergic receptors are expected to supply us in the future with pharmaceuticals which are able to combat in a range of neurological/psychiatric diseases the accompanying cognitive deterioration.
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Affiliation(s)
- Peter Illes
- School of Acupuncture and Tuina, Chengdu University of Traditonal Chinese Medicine, Chengdu 610075, China; Rudolf Boehm Institute for Pharmacology and Toxicology, University of Leipzig, 04107 Leipzig, Germany; International Joint Research Center for Purinergic Signaling, Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China.
| | - Henning Ulrich
- International Joint Research Center for Purinergic Signaling, Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China; Department of Biochemistry and Molecular Biology, Chemistry Institute, University of Sao Paulo (USP), Sao Paulo, Brazil
| | - Jiang-Fan Chen
- The Molecular Neuropharmacology Laboratory and the Eye-Brain Research Center, The State Key Laboratory of Ophthalmology, Optometry and Vision Science, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Whenzhou 325000, China
| | - Yong Tang
- School of Acupuncture and Tuina, Chengdu University of Traditonal Chinese Medicine, Chengdu 610075, China; International Joint Research Center for Purinergic Signaling, Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China; Acupuncture and Chronobiology Key Laboratory of Sichuan Province, School of Health and Rehabilitation, Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China.
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Alnafisah R, Lundh A, Asah SM, Hoeflinger J, Wolfinger A, Hamoud AR, McCullumsmith RE, O'Donovan SM. Altered purinergic receptor expression in the frontal cortex in schizophrenia. SCHIZOPHRENIA (HEIDELBERG, GERMANY) 2022; 8:96. [PMID: 36376358 PMCID: PMC9663420 DOI: 10.1038/s41537-022-00312-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 11/03/2022] [Indexed: 04/27/2023]
Abstract
ATP functions as a neurotransmitter, acting on the ubiquitously expressed family of purinergic P2 receptors. In schizophrenia (SCZ), the pathways that modulate extracellular ATP and its catabolism to adenosine are dysregulated. However, the effects of altered ATP availability on P2 receptor expression in the brain in SCZ have not been assessed. We assayed P2 receptor mRNA and protein expression in the DLPFC and ACC in subjects diagnosed with SCZ and matched, non-psychiatrically ill controls (n = 20-22/group). P2RX7, P2RX4 and male P2RX5 mRNA expression were significantly increased (p < 0.05) in the DLPFC in SCZ. Expression of P2RX7 protein isoform was also significantly increased (p < 0.05) in the DLPFC in SCZ. Significant increases in P2RX4 and male P2RX5 mRNA expression may be associated with antipsychotic medication effects. We found that P2RX4 and P2RX7 mRNA are significantly correlated with the inflammatory marker SERPINA3, and may suggest an association between upregulated P2XR and neuroinflammation in SCZ. These findings lend support for brain-region dependent dysregulation of the purinergic system in SCZ.
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Affiliation(s)
- Rawan Alnafisah
- Department of Neurosciences, University of Toledo, Toledo, OH, USA
| | - Anna Lundh
- Department of Neurosciences, University of Toledo, Toledo, OH, USA
| | - Sophie M Asah
- Department of Neurosciences, University of Toledo, Toledo, OH, USA
| | - Julie Hoeflinger
- Department of Neurosciences, University of Toledo, Toledo, OH, USA
| | - Alyssa Wolfinger
- Department of Neurosciences, University of Toledo, Toledo, OH, USA
| | | | - Robert E McCullumsmith
- Department of Neurosciences, University of Toledo, Toledo, OH, USA
- Neurosciences Institute, Promedica, Toledo, OH, USA
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Schneider S, Merfort I, Idzko M, Zech A. Blocking P2X purinoceptor 4 signalling alleviates cigarette smoke induced pulmonary inflammation. Respir Res 2022; 23:148. [PMID: 35676684 PMCID: PMC9175376 DOI: 10.1186/s12931-022-02072-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 05/27/2022] [Indexed: 12/31/2022] Open
Abstract
Background Chronic obstructive pulmonary disease (COPD) is associated with elevated ATP levels in the extracellular space. Once released, ATP serves as danger signal modulating immune responses by activating purinergic receptors. Accordingly, purinergic signalling has been implicated in respiratory inflammation associated with cigarette smoke exposure. However, the role of P2X4-signalling has not been fully elucidated yet.
Methods Here, we analysed the P2X4 mRNA expression in COPD patients as well as cigarette smoke-exposed mice. Furthermore, P2X4-signalling was blocked by either using a specific antagonist or genetic depletion of P2rx4 in mice applied to an acute and prolonged model of cigarette smoke exposure. Finally, we inhibited P2X4-signalling in macrophages derived from THP-1 before stimulation with cigarette smoke extract. Results COPD patients exhibited an increased P2X4 mRNA expression in cells isolated from the bronchoalveolar lavage fluid and peripheral mononuclear cells. Similarly, P2rx4 expression was elevated in lung tissue of mice exposed to cigarette smoke. Blocking P2X4-signalling in mice alleviated cigarette smoke induced airway inflammation as well as lung parenchyma destruction. Additionally, human macrophages derived from THP-1 cells released reduced concentrations of proinflammatory cytokines in response to cigarette smoke extract stimulation when P2X4 was inhibited. Conclusion Taken together, we provide evidence that P2X4-signalling promotes innate immunity in the immunopathologic responses induced by cigarette smoke exposure. Supplementary Information The online version contains supplementary material available at 10.1186/s12931-022-02072-z.
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Qiao C, Tang Y, Li Q, Zhu X, Peng X, Zhao R. ATP-gated P2X7 receptor as a potential target for prostate cancer. Hum Cell 2022; 35:1346-1354. [PMID: 35657562 DOI: 10.1007/s13577-022-00729-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 05/18/2022] [Indexed: 12/24/2022]
Abstract
Prostate cancer is the most common malignancy of the male genitourinary system and is one of the leading causes of male cancer death. The P2X7 receptor is an important member of purine receptor family. It is a gated ion channel with adenosine triphosphate (ATP) as the ligand, which exists in a variety of immune tissues and cells and can be involved in tumorigenesis and tumor progression. Studies have shown that the P2X7 receptor is abnormally expressed in prostate cancer, and is related to the level of prostate-specific antigen, P2X7 receptor may be an early biomarker of prostate cancer. The P2X7 receptor is essential in the occurrence and development of prostate cancer. The P2X7 receptor mainly affects the invasion and metastasis of prostate cancer cells through epithelial mesenchymal transition/invasion-related genes and the PI3K/AKT and ERK1/2 signaling pathways. The P2X7 receptor could be a promising therapeutic target for prostate cancer.
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Affiliation(s)
- Cuicui Qiao
- School of Laboratory Medicine, Weifang Medical University, Weifang, 261053, Shandong, China
| | - Yiqing Tang
- School of Laboratory Medicine, Weifang Medical University, Weifang, 261053, Shandong, China
| | - Qianqian Li
- School of Laboratory Medicine, Weifang Medical University, Weifang, 261053, Shandong, China
| | - Xiaodi Zhu
- School of Laboratory Medicine, Weifang Medical University, Weifang, 261053, Shandong, China
| | - Xiaoxiang Peng
- School of Laboratory Medicine, Weifang Medical University, Weifang, 261053, Shandong, China
| | - Ronglan Zhao
- School of Laboratory Medicine, Weifang Medical University, Weifang, 261053, Shandong, China.
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Díaz-Muñoz M, Hernández-Muñoz R, Butanda-Ochoa A. Structure-activity features of purines and their receptors: implications in cell physiopathology. MOLECULAR BIOMEDICINE 2022; 3:5. [PMID: 35079944 PMCID: PMC8789959 DOI: 10.1186/s43556-022-00068-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 01/19/2022] [Indexed: 11/21/2022] Open
Abstract
The purine molecular structure consists of fused pyrimidine and imidazole rings. Purines are main pieces that conform the structure of nucleic acids which rule the inheritance processes. Purines also work as metabolic intermediates in different cell functions and as messengers in the signaling pathways throughout cellular communication. Purines, mainly ATP and adenosine (ADO), perform their functional and pharmacological properties because of their structural/chemical characteristics that make them either targets of mutagenesis, mother frameworks for designing molecules with controlled effects (e.g. anti-cancer), or chemical donors (e.g., of methyl groups, which represent a potential chemoprotective action against cancer). Purines functions also come from their effect on specific receptors, channel-linked and G-protein coupled for ATP, and exclusively G-coupled receptors for ADO (also known as ADORAs), which are involved in cell signaling pathways, there, purines work as chemical messengers with autocrine, paracrine, and endocrine actions that regulate cell metabolism and immune response in tumor progression which depends on the receptor types involved in these signals. Purines also have antioxidant and anti-inflammatory properties and participate in the cell energy homeostasis. Therefore, purine physiology is important for a variety of functions relevant to cellular health; thus, when these molecules present a homeostatic imbalance, the stability and survival of the cellular systems become compromised.
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Affiliation(s)
- Mauricio Díaz-Muñoz
- Departamento de Neurobiología Celular Y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, UNAM, Boulevard Juriquilla 3001, C.P. 76230, Juriquilla, Querétaro, México
| | - Rolando Hernández-Muñoz
- Departamento de Biología Celular Y Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, UNAM, Ciudad Universitaria/Circuito Exterior, C.P. 04510, Ciudad de México, México
| | - Armando Butanda-Ochoa
- Departamento de Biología Celular Y Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, UNAM, Ciudad Universitaria/Circuito Exterior, C.P. 04510, Ciudad de México, México.
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Role of microglia and P2X4 receptors in chronic pain. Pain Rep 2021; 6:e864. [PMID: 33981920 PMCID: PMC8108579 DOI: 10.1097/pr9.0000000000000864] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/01/2020] [Accepted: 09/08/2020] [Indexed: 12/15/2022] Open
Abstract
This study summarizes current understanding of the role of microglia and P2X4 receptor in chronic pain including neuropathic pain and of their therapeutic potential. Pain plays an indispensable role as an alarm system to protect us from dangers or injuries. However, neuropathic pain, a debilitating pain condition caused by damage to the nervous system, persists for a long period even in the absence of dangerous stimuli or after injuries have healed. In this condition, pain becomes a disease itself rather than the alarm system and is often resistant to currently available medications. A growing body of evidence indicates that microglia, a type of macrophages residing in the central nervous system, play a crucial role in the pathogenesis of neuropathic pain. Whenever microglia in the spinal cord detect a damaging signal within the nervous system, they become activated and cause diverse alterations that change neural excitability, leading to the development of neuropathic pain. For over a decade, several lines of molecular and cellular mechanisms that define microglial activation and subsequently altered pain transmission have been proposed. In particular, P2X4 receptors (a subtype of purinergic receptors) expressed by microglia have been investigated as an essential molecule for neuropathic pain. In this review article, we describe our understanding of the mechanisms by which activated microglia cause neuropathic pain through P2X4 receptors, their involvement in several pathological contexts, and recent efforts to develop new drugs targeting microglia and P2X4 receptors.
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Kanellopoulos JM, Almeida-da-Silva CLC, Rüütel Boudinot S, Ojcius DM. Structural and Functional Features of the P2X4 Receptor: An Immunological Perspective. Front Immunol 2021; 12:645834. [PMID: 33897694 PMCID: PMC8059410 DOI: 10.3389/fimmu.2021.645834] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 03/04/2021] [Indexed: 12/14/2022] Open
Abstract
Extracellular nucleotides are important mediators of activation, triggering various responses through plasma membrane P2 and P1 receptors. P2 receptors are further subdivided into ionotropic P2X receptors and G protein-coupled P2Y receptors. P2X4 is an ATP-gated cation channel broadly expressed in most tissues of the body. Within the P2X family, P2X4 has a unique subcellular distribution, being preferentially localized in lysosomes. In these organelles, high ATP concentrations do not trigger P2X4 because of the low pH. However, when the pH increases to 7.4, P2X4 can be stimulated by intra-lysosomal ATP, which is in its active, tetra-anionic form. Elucidation of P2X4, P2X3 and P2X7 structures has shed some light on the functional differences between these purinergic receptors. The potential interaction between P2X4 and P2X7 has been extensively studied. Despite intensive effort, it has not been possible yet to determine whether P2X4 and P2X7 interact as heterotrimers or homotrimers at the plasma membrane. However, several publications have shown that functional interactions between P2X4 and P2X7 do occur. Importantly, these studies indicate that P2X4 potentiates P2X7-dependent activation of inflammasomes, leading to increased release of IL-1β and IL-18. The role of P2X4 in various diseases could be beneficial or deleterious even though the pathophysiological mechanisms involved are still poorly defined. However, in diseases whose physiopathology involves activation of the NLRP3 inflammasome, P2X4 was found to exacerbate severity of disease. The recent production of monoclonal antibodies specific for the human and mouse P2X4, some of which are endowed with agonist or antagonist properties, raises the possibility that they could be used therapeutically. Analysis of single nucleotide polymorphisms of the human P2RX4 gene has uncovered the association of P2RX4 gene variants with susceptibility to several human diseases.
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Affiliation(s)
- Jean M Kanellopoulos
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | | | - Sirje Rüütel Boudinot
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - David M Ojcius
- Department of Biomedical Sciences, University of the Pacific, Arthur A. Dugoni School of Dentistry, San Francisco, CA, United States
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Dias L, Lopes CR, Gonçalves FQ, Nunes A, Pochmann D, Machado NJ, Tomé AR, Agostinho P, Cunha RA. Crosstalk Between ATP-P 2X7 and Adenosine A 2A Receptors Controlling Neuroinflammation in Rats Subject to Repeated Restraint Stress. Front Cell Neurosci 2021; 15:639322. [PMID: 33732112 PMCID: PMC7957057 DOI: 10.3389/fncel.2021.639322] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 02/08/2021] [Indexed: 01/02/2023] Open
Abstract
Depressive conditions precipitated by repeated stress are a major socio-economical burden in Western countries. Previous studies showed that ATP-P2X7 receptors (P2X7R) and adenosine A2A receptors (A2AR) antagonists attenuate behavioral modifications upon exposure to repeated stress. Since it is unknown if these two purinergic modulation systems work independently, we now investigated a putative interplay between P2X7R and A2AR. Adult rats exposed to restraint stress for 14 days displayed an anxious (thigmotaxis, elevated plus maze), depressive (anhedonia, increased immobility), and amnesic (modified Y maze, object displacement) profile, together with increased expression of Iba-1 (a marker of microglia “activation”) and interleukin-1β (IL1β) and tumor necrosis factor α (TNFα; proinflammatory cytokines) and an up-regulation of P2X7R (mRNA) and A2AR (receptor binding) in the hippocampus and prefrontal cortex. All these features were attenuated by the P2X7R-preferring antagonist brilliant blue G (BBG, 45 mg/kg, i.p.) or by caffeine (0.3 g/L, p.o.), which affords neuroprotection through A2AR blockade. Notably, BBG attenuated A2AR upregulation and caffeine attenuated P2X7R upregulation. In microglial N9 cells, the P2X7R agonist BzATP (100 μM) or the A2AR agonist CGS26180 (100 nM) increased calcium levels, which was abrogated by the P2X7R antagonist JNJ47965567 (1 μM) and by the A2AR antagonist SCH58261 (50 nM), respectively; notably JNJ47965567 prevented the effect of CGS21680 and the effect of BzATP was attenuated by SCH58261 and increased by CGS21680. These results provide the first demonstration of a functional interaction between P2X7R and A2AR controlling microglia reactivity likely involved in behavioral adaptive responses to stress and are illustrative of a cooperation between the two arms of the purinergic system in the control of brain function.
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Affiliation(s)
- Liliana Dias
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Cátia R Lopes
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Francisco Q Gonçalves
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Ana Nunes
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Daniela Pochmann
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Nuno J Machado
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Angelo R Tomé
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Coimbra, Portugal
| | - Paula Agostinho
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Rodrigo A Cunha
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, Coimbra, Portugal
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Zhu X, Li Q, Song W, Peng X, Zhao R. P2X7 receptor: a critical regulator and potential target for breast cancer. J Mol Med (Berl) 2021; 99:349-358. [PMID: 33486566 DOI: 10.1007/s00109-021-02041-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 01/13/2021] [Accepted: 01/14/2021] [Indexed: 12/24/2022]
Abstract
Breast cancer is currently the most common cancer and the leading cause of cancer death among women worldwide. Advanced breast cancer is prone to metastasis, and there is currently no drug to cure metastatic breast cancer. The purinergic ligand-gated ion channel 7 receptor is an ATP-gated nonselective cation channel receptor and is involved in signal transduction, growth regulation, cytokine secretion, and tumor cell development. Recent studies have shown that upregulation of the P2X7 receptor in breast cancer can mediate AKT signaling pathways, Ca2 þ-activated SK3 potassium channels, and EMT and regulate the secretion of small extracellular vesicles to promote breast cancer invasion and migration, which are affected by factors such as hypoxia and ATP. In addition, studies have shown that microRNAs can bind to the 3' untranslated region of the P2X7 receptor, which affects the occurrence and development of breast cancer by upregulating and downregulating P2X7 receptor expression. Studies have shown that new P2X7 receptor inhibitors, such as emodin and Uncaria tomentosa, can inhibit P2X7 receptor-mediated breast cancer invasion and are expected to be used clinically. This article reviews the research progress on the relationship between the P2X7 receptor and breast cancer to provide new ideas and a basis for clinical diagnosis and treatment.
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Affiliation(s)
- Xiaodi Zhu
- School of Medical Laboratory, Weifang Medical University, Weifang, Shandong, China
| | - Qianqian Li
- School of Medical Laboratory, Weifang Medical University, Weifang, Shandong, China
| | - Wei Song
- School of Medical Laboratory, Weifang Medical University, Weifang, Shandong, China
| | - Xiaoxiang Peng
- School of Medical Laboratory, Weifang Medical University, Weifang, Shandong, China.
| | - Ronglan Zhao
- School of Medical Laboratory, Weifang Medical University, Weifang, Shandong, China.
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Martínez-Cuesta MÁ, Blanch-Ruiz MA, Ortega-Luna R, Sánchez-López A, Álvarez Á. Structural and Functional Basis for Understanding the Biological Significance of P2X7 Receptor. Int J Mol Sci 2020; 21:ijms21228454. [PMID: 33182829 PMCID: PMC7696479 DOI: 10.3390/ijms21228454] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/04/2020] [Accepted: 11/06/2020] [Indexed: 12/11/2022] Open
Abstract
The P2X7 receptor (P2X7R) possesses a unique structure associated to an as yet not fully understood mechanism of action that facilitates cell permeability to large ionic molecules through the receptor itself and/or nearby membrane proteins. High extracellular adenosine triphosphate (ATP) levels—inexistent in physiological conditions—are required for the receptor to be triggered and contribute to its role in cell damage signaling. The inconsistent data on its activation pathways and the few studies performed in natively expressed human P2X7R have led us to review the structure, activation pathways, and specific cellular location of P2X7R in order to analyze its biological relevance. The ATP-gated P2X7R is a homo-trimeric receptor channel that is occasionally hetero-trimeric and highly polymorphic, with at least nine human splice variants. It is localized predominantly in the cellular membrane and has a characteristic plasticity due to an extended C-termini, which confers it the capacity of interacting with membrane structural compounds and/or intracellular signaling messengers to mediate flexible transduction pathways. Diverse drugs and a few endogenous molecules have been highlighted as extracellular allosteric modulators of P2X7R. Therefore, studies in human cells that constitutively express P2X7R need to investigate the precise endogenous mediator located nearby the activation/modulation domains of the receptor. Such research could help us understand the possible physiological ATP-mediated P2X7R homeostasis signaling.
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Affiliation(s)
- María Ángeles Martínez-Cuesta
- Departamento de Farmacología, Facultad de Medicina y Odontología, Universidad de Valencia, 46010 Valencia, Spain; (M.A.B.-R.); (R.O.-L.); (A.S.-L.)
- CIBERehd, Valencia, Spain
- Correspondence: (M.Á.M.-C.); (Á.Á.); Tel.: +34-963983716 (M.Á.M.-C.); +34-963864898 (Á.Á.)
| | - María Amparo Blanch-Ruiz
- Departamento de Farmacología, Facultad de Medicina y Odontología, Universidad de Valencia, 46010 Valencia, Spain; (M.A.B.-R.); (R.O.-L.); (A.S.-L.)
| | - Raquel Ortega-Luna
- Departamento de Farmacología, Facultad de Medicina y Odontología, Universidad de Valencia, 46010 Valencia, Spain; (M.A.B.-R.); (R.O.-L.); (A.S.-L.)
| | - Ainhoa Sánchez-López
- Departamento de Farmacología, Facultad de Medicina y Odontología, Universidad de Valencia, 46010 Valencia, Spain; (M.A.B.-R.); (R.O.-L.); (A.S.-L.)
| | - Ángeles Álvarez
- Departamento de Farmacología, Facultad de Medicina y Odontología, Universidad de Valencia, 46010 Valencia, Spain; (M.A.B.-R.); (R.O.-L.); (A.S.-L.)
- CIBERehd, Valencia, Spain
- Correspondence: (M.Á.M.-C.); (Á.Á.); Tel.: +34-963983716 (M.Á.M.-C.); +34-963864898 (Á.Á.)
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13
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Extracellular ATP as an Inter-Kingdom Signaling Molecule: Release Mechanisms by Bacteria and Its Implication on the Host. Int J Mol Sci 2020; 21:ijms21155590. [PMID: 32759857 PMCID: PMC7432876 DOI: 10.3390/ijms21155590] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 07/29/2020] [Accepted: 08/01/2020] [Indexed: 12/17/2022] Open
Abstract
The purine adenosine 5′-triphosphate (ATP) is not only a universal intracellular energy carrier but plays also an important role as extracellular signaling molecule. Purinergic signaling is involved in many physiological and pathological processes like coagulation, inflammation, or sepsis in mammals. ATP is well-known as a messenger for intercellular communications in multicellular organisms, but phylogenetically much older unicellular organisms like yeast or bacteria use ATP as an extracellular signaling molecule as well. However, the mechanisms of ATP secretion by bacteria and its extracellular implications still have to be elucidated. This review will provide an overview of the current knowledge about bacterial extracellular ATP (eATP) under homeostatic conditions and during growth. Possible secretion mechanisms of ATP by bacteria will be discussed and implications of bacterial ATP are shown, with a focus on bacteria–host interactions.
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14
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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.
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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
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15
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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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16
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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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17
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Soto P, Gaete PS, Fuentes C, Lozano B, Naulin PA, Figueroa XF, Barrera NP. Function of P2X4 Receptors Is Directly Modulated by a 1:1 Stoichiometric Interaction With 5-HT 3A Receptors. Front Cell Neurosci 2020; 14:106. [PMID: 32431598 PMCID: PMC7214622 DOI: 10.3389/fncel.2020.00106] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 04/07/2020] [Indexed: 12/30/2022] Open
Abstract
Interacting receptors at the neuronal plasma membrane represent an additional regulatory mode for intracellular transduction pathways. P2X4 receptor triggers fast neurotransmission responses via a transient increase in intracellular Ca2+ levels. It has been proposed that the P2X4 receptor interacts with the 5-HT3A receptor in hippocampal neurons, but their binding stoichiometry and the role of P2X4 receptor activation by ATP on this crosstalking system remains unknown. Via pull-down assays, total internal reflection fluorescence (TIRF) microscopy measurements of the receptors colocalization and expression at the plasma membrane, and atomic force microscopy (AFM) imaging, we have demonstrated that P2X4/5-HT3A receptor complexes can interact with each other in a 1:1 stoichiometric manner that is preserved after ATP binding. Also, macromolecular docking followed by 100 ns molecular dynamics (MD) simulations suggested that the interaction energy of the P2X4 receptor with 5-HT3A receptor is similar at the holo and the apo state of the P2X4 receptor, and the interacting 5-HT3A receptor decreased the ATP binding energy of P2X4 receptor. Finally, the P2X4 receptor-dependent Ca2+ mobilization is inhibited by the 5-HT3A interacting receptor. Altogether, these findings provide novel molecular insights into the allosteric regulation of P2X4/5-HT3A receptor complex in lipid bilayers of living cells via stoichiometric association, rather than accumulation or unspecific clustering of complexes.
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Affiliation(s)
- Paola Soto
- Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Pablo S Gaete
- Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Christian Fuentes
- Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Benjamin Lozano
- Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Pamela A Naulin
- Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Xavier F Figueroa
- Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Nelson Patricio Barrera
- Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
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18
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Khalafalla MG, Woods LT, Jasmer KJ, Forti KM, Camden JM, Jensen JL, Limesand KH, Galtung HK, Weisman GA. P2 Receptors as Therapeutic Targets in the Salivary Gland: From Physiology to Dysfunction. Front Pharmacol 2020; 11:222. [PMID: 32231563 PMCID: PMC7082426 DOI: 10.3389/fphar.2020.00222] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 02/18/2020] [Indexed: 12/12/2022] Open
Abstract
Although often overlooked in our daily lives, saliva performs a host of necessary physiological functions, including lubricating and protecting the oral cavity, facilitating taste sensation and digestion and maintaining tooth enamel. Therefore, salivary gland dysfunction and hyposalivation, often resulting from pathogenesis of the autoimmune disease Sjögren's syndrome or from radiotherapy of the head and neck region during cancer treatment, severely reduce the quality of life of afflicted patients and can lead to dental caries, periodontitis, digestive disorders, loss of taste and difficulty speaking. Since their initial discovery in the 1970s, P2 purinergic receptors for extracellular nucleotides, including ATP-gated ion channel P2X and G protein-coupled P2Y receptors, have been shown to mediate physiological processes in numerous tissues, including the salivary glands where P2 receptors represent a link between canonical and non-canonical saliva secretion. Additionally, extracellular nucleotides released during periods of cellular stress and inflammation act as a tissue alarmin to coordinate immunological and tissue repair responses through P2 receptor activation. Accordingly, P2 receptors have gained widespread clinical interest with agonists and antagonists either currently undergoing clinical trials or already approved for human use. Here, we review the contributions of P2 receptors to salivary gland function and describe their role in salivary gland dysfunction. We further consider their potential as therapeutic targets to promote physiological saliva flow, prevent salivary gland inflammation and enhance tissue regeneration.
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Affiliation(s)
- Mahmoud G. Khalafalla
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Lucas T. Woods
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
| | - Kimberly J. Jasmer
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
| | - Kevin Muñoz Forti
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
| | - Jean M. Camden
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
| | - Janicke L. Jensen
- Institute of Clinical Dentistry, Section of Oral Surgery and Oral Medicine, University of Oslo, Oslo, Norway
| | - Kirsten H. Limesand
- Department of Nutritional Sciences, University of Arizona, Tucson, AZ, United States
| | - Hilde K. Galtung
- Institute of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
| | - Gary A. Weisman
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
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19
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Illes P, Verkhratsky A, Tang Y. Pathological ATPergic Signaling in Major Depression and Bipolar Disorder. Front Mol Neurosci 2020; 12:331. [PMID: 32076399 PMCID: PMC7006450 DOI: 10.3389/fnmol.2019.00331] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Accepted: 12/26/2019] [Indexed: 12/11/2022] Open
Abstract
The mood disorders, major depression (MD) and bipolar disorder (BD), have a high lifetime prevalence in the human population and accordingly generate huge costs for health care. Efficient, rapidly acting, and side-effect-free pharmaceuticals are hitherto not available, and therefore, the identification of new therapeutic targets is an imperative task for (pre)clinical research. Such a target may be the purinergic P2X7 receptor (P2X7R), which is localized in the central nervous system (CNS) at microglial and neuroglial cells mediating neuroinflammation. MD and BD are due to neuroinflammation caused in the first line by the release of the pro-inflammatory cytokine interleukin-1β (IL-1β) from the microglia. IL-1β in turn induces the secretion of corticotropin-releasing hormone (CRH) and in consequence the secretion of adrenocorticotropic hormone (ACTH) and cortisol, which together with a plethora of further cytokines/chemokines lead to mood disorders. A number of biochemical/molecular biological measurements including the use of P2X7R- or IL-1β-deficient mice confirmed this chain of events. More recent studies showed that a decrease in the astrocytic release of ATP in the prefrontal cortex and hippocampus is a major cause of mood disorders. It is an attractive hypothesis that compensatory increases in P2X7Rs in these areas of the brain are the immediate actuators of MD and BD. Hence, blood-brain barrier-permeable P2X7R antagonists may be promising therapeutic tools to improve depressive disorders in humans.
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Affiliation(s)
- Peter Illes
- Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Universität Leipzig, Leipzig, Germany.,Acupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Alexei Verkhratsky
- Faculty of Life Sciences, The University of Manchester, Manchester, United Kingdom.,Achucarro Centre for Neuroscience, Ikerbasque, Basque Foundation for Science, Bilbao, Spain
| | - Yong Tang
- Acupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine, Chengdu, China
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20
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Vallon V, Unwin R, Inscho EW, Leipziger J, Kishore BK. Extracellular Nucleotides and P2 Receptors in Renal Function. Physiol Rev 2019; 100:211-269. [PMID: 31437091 DOI: 10.1152/physrev.00038.2018] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The understanding of the nucleotide/P2 receptor system in the regulation of renal hemodynamics and transport function has grown exponentially over the last 20 yr. This review attempts to integrate the available data while also identifying areas of missing information. First, the determinants of nucleotide concentrations in the interstitial and tubular fluids of the kidney are described, including mechanisms of cellular release of nucleotides and their extracellular breakdown. Then the renal cell membrane expression of P2X and P2Y receptors is discussed in the context of their effects on renal vascular and tubular functions. Attention is paid to effects on the cortical vasculature and intraglomerular structures, autoregulation of renal blood flow, tubuloglomerular feedback, and the control of medullary blood flow. The role of the nucleotide/P2 receptor system in the autocrine/paracrine regulation of sodium and fluid transport in the tubular and collecting duct system is outlined together with its role in integrative sodium and fluid homeostasis and blood pressure control. The final section summarizes the rapidly growing evidence indicating a prominent role of the extracellular nucleotide/P2 receptor system in the pathophysiology of the kidney and aims to identify potential therapeutic opportunities, including hypertension, lithium-induced nephropathy, polycystic kidney disease, and kidney inflammation. We are only beginning to unravel the distinct physiological and pathophysiological influences of the extracellular nucleotide/P2 receptor system and the associated therapeutic perspectives.
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Affiliation(s)
- Volker Vallon
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
| | - Robert Unwin
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
| | - Edward W Inscho
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
| | - Jens Leipziger
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
| | - Bellamkonda K Kishore
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
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21
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Kopp R, Krautloher A, Ramírez-Fernández A, Nicke A. P2X7 Interactions and Signaling - Making Head or Tail of It. Front Mol Neurosci 2019; 12:183. [PMID: 31440138 PMCID: PMC6693442 DOI: 10.3389/fnmol.2019.00183] [Citation(s) in RCA: 155] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 07/11/2019] [Indexed: 12/14/2022] Open
Abstract
Extracellular adenine nucleotides play important roles in cell-cell communication and tissue homeostasis. High concentrations of extracellular ATP released by dying cells are sensed as a danger signal by the P2X7 receptor, a non-specific cation channel. Studies in P2X7 knockout mice and numerous disease models have demonstrated an important role of this receptor in inflammatory processes. P2X7 activation has been shown to induce a variety of cellular responses that are not usually associated with ion channel function, for example changes in the plasma membrane composition and morphology, ectodomain shedding, activation of lipases, kinases, and transcription factors, as well as cytokine release and apoptosis. In contrast to all other P2X family members, the P2X7 receptor contains a long intracellular C-terminus that constitutes 40% of the whole protein and is considered essential for most of these effects. So far, over 50 different proteins have been identified to physically interact with the P2X7 receptor. However, few of these interactions have been confirmed in independent studies and for the majority of these proteins, the interaction domains and the physiological consequences of the interactions are only poorly described. Also, while the structure of the P2X7 extracellular domain has recently been resolved, information about the organization and structure of its C-terminal tail remains elusive. After shortly describing the structure and assembly of the P2X7 receptor, this review gives an update of the identified or proposed interaction domains within the P2X7 C-terminus, describes signaling pathways in which this receptor has been involved, and provides an overlook of the identified interaction partners.
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Affiliation(s)
- Robin Kopp
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Anna Krautloher
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Antonio Ramírez-Fernández
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Annette Nicke
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, Munich, Germany
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22
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Guerra Martinez C. P2X7 receptor in cardiovascular disease: The heart side. Clin Exp Pharmacol Physiol 2019; 46:513-526. [PMID: 30834550 DOI: 10.1111/1440-1681.13079] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 02/21/2019] [Accepted: 02/28/2019] [Indexed: 01/10/2023]
Abstract
The P2X7 receptor is a ligand-gated purinergic receptor activated by extracellular ATP. The receptor is highly expressed in immune cells and in the brain, and, upon activation, the P2X7 receptor allows a cation flux, leading to the distinct activation of intracellular signalling pathways as the secretion of pro-inflammatory cytokines, and modulation of cell survival. Through these molecular mechanisms, P2X7 is known to play important roles in physiology and pathophysiology of a wide spectrum of diseases, including cancer, inflammatory diseases, neurological, respiratory and more recently cardiovascular diseases. Recent studies demonstrated that the P2X7 could modulate the assembly of the NLRP3 inflammasome, leading to the secretion of pro-inflammatory factors and worsen the cardiac disease phenotypes. This review discusses the critical molecular function of P2X7 in the modulation of the onset, progression and resolution of cardiovascular diseases and analyses the putative future use of P2X7-based therapies that modulate the IL-1β secretion arm and direct P2X7 antagonists.
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Affiliation(s)
- Camila Guerra Martinez
- Department of Microbial Pathogenesis and Immunology, Texas A&M University, College Station, Texas
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23
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Antonioli L, Blandizzi C, Fornai M, Pacher P, Lee HT, Haskó G. P2X4 receptors, immunity, and sepsis. Curr Opin Pharmacol 2019; 47:65-74. [PMID: 30921560 DOI: 10.1016/j.coph.2019.02.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 02/21/2019] [Accepted: 02/22/2019] [Indexed: 12/20/2022]
Abstract
Sepsis is life-threatening systemic organ dysfunction caused by a deregulated host response to an infectious insult. Currently, the treatment of sepsis is limited to the use of antibiotics, fluids, and cardiovascular/respiratory support. Despite these interventions, septic mortality remains high, with reduced life quality in survivors. For this reason, the identification of novel drug targets is a pressing task of modern pharmacology. According to a recent research, it appears that P2 purinergic receptors, which can regulate the host's response to infections, have been identified as potential targets for the treatment of sepsis. Among P2 receptors, the P2X4 receptor has recently captured the attention of the research community owing to its role in protecting against infections, inflammation, and organ injury. The present review provides an outline of the role played by P2X4 receptors in the modulation of the host's response to sepsis and the promise that targeting this receptor holds in the treatment of sepsis.
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Affiliation(s)
- Luca Antonioli
- Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy; Department of Anesthesiology, Columbia University, New York, NY, 10032, USA
| | - Corrado Blandizzi
- Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy
| | - Matteo Fornai
- Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy
| | - Pál Pacher
- Laboratory of Cardiovascular Physiology and Tissue Injury, National Institutes of Health/NIAAA, Bethesda, MD 20892, USA
| | - H Thomas Lee
- Department of Anesthesiology, Columbia University, New York, NY, 10032, USA
| | - György Haskó
- Department of Anesthesiology, Columbia University, New York, NY, 10032, USA.
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24
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Zou L, Gong Y, Liu S, Liang S. Natural compounds acting at P2 receptors alleviate peripheral neuropathy. Brain Res Bull 2018; 151:125-131. [PMID: 30599217 DOI: 10.1016/j.brainresbull.2018.12.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 12/23/2018] [Accepted: 12/26/2018] [Indexed: 12/29/2022]
Abstract
Neuropathic pain is generally resistant to currently available treatments, and it is often a consequence of nerve injury due to surgery, diabetes or infection. Myocardial ischemic nociceptive signaling increases the sympathoexcitatory reflex to aggravate myocardial injury. Elucidation of the pathogenetic factors might provide a target for optimal treatment. Abundant evidence in the literature suggests that P2X and P2Y receptors play important roles in signal transmission. Traditional Chinese medicines, such as emodin, puerarin and resveratrol, antagonize nociceptive transmission mediated by purinergic 2 (P2) receptors in primary afferent neurons. This review summarizes recently published data on P2 receptor-mediated neuropathic pain and myocardial ischemia in dorsal root ganglia (DRG), superior cervical ganglia (SCG) and stellate ganglia (SG), with a special focus on the beneficial role of natural compounds.
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Affiliation(s)
- Lifang Zou
- Neuropharmacological Labratory of Physiology Department, Medical School of Nanchang University, Nanchang, Jiangxi, 330006, Peoples Republic of China; Jiangxi Provincial Key Laboratory of autonomic nervous function and disease, Nanchang, Jiangxi, 330006, People's Republic of China
| | - Yingxin Gong
- Undergraduate student of the First Clinical Department, Medical School of Nanchang University, Nanchang, Jiangxi, 330006, People's Republic of China
| | - Shuangmei Liu
- Neuropharmacological Labratory of Physiology Department, Medical School of Nanchang University, Nanchang, Jiangxi, 330006, Peoples Republic of China; Jiangxi Provincial Key Laboratory of autonomic nervous function and disease, Nanchang, Jiangxi, 330006, People's Republic of China
| | - Shangdong Liang
- Neuropharmacological Labratory of Physiology Department, Medical School of Nanchang University, Nanchang, Jiangxi, 330006, Peoples Republic of China; Jiangxi Provincial Key Laboratory of autonomic nervous function and disease, Nanchang, Jiangxi, 330006, People's Republic of China.
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25
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Dunton CL, Purves JT, Hughes FM, Jin H, Nagatomi J. Elevated hydrostatic pressure stimulates ATP release which mediates activation of the NLRP3 inflammasome via P2X 4 in rat urothelial cells. Int Urol Nephrol 2018; 50:1607-1617. [PMID: 30099658 PMCID: PMC6129973 DOI: 10.1007/s11255-018-1948-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 07/30/2018] [Indexed: 02/06/2023]
Abstract
Partial bladder outlet obstruction (pBOO) is a prevalent urological condition commonly accompanied by increased intravesical pressure, inflammation, and fibrosis. Studies have demonstrated that pBOO results in increased NLRP3 inflammasome and caspase-1 activation and that ATP is released from urothelial cells in response to elevated pressure. In the present study, we investigated the role of elevated pressure in triggering caspase-1 activation via purinergic receptors activation in urothelial cells. Rat urothelial cell line, MYP3 cells, was subjected to hydrostatic pressures of 15 cmH2O for 60 min, or 40 cmH2O for 1 min to simulate elevated storage and voiding pressure conditions, respectively. ATP concentration in the supernatant media and intracellular caspase-1 activity in cell lysates were measured. Pressure experiments were repeated in the presence of antagonists for purinergic receptors to determine the mechanism for pressure-induced caspase-1 activation. Exposure of MYP3 cells to both pressure conditions resulted in an increase in extracellular ATP levels and intracellular caspase-1 activity. Treatment with P2X7 antagonist led to a decrease in pressure-induced ATP release by MYP3 cells, while P2X4 antagonist had no effect but both antagonists inhibited pressure-induced caspase-1 activation. Moreover, when MYP3 cells were treated with extracellular ATP (500 µM), P2X4 antagonist inhibited ATP-induced caspase-1 activation, but not P2X7 antagonist. We concluded that pressure-induced extracellular ATP in urothelial cells is amplified by P2X7 receptor activation and ATP-induced-ATP release. The amplified ATP signal then activates P2X4 receptors, which mediate activation of the caspase-1 inflammatory response.
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Affiliation(s)
- Cody L Dunton
- Department of Bioengineering, Clemson University, Clemson, SC, USA
| | - J Todd Purves
- Department of Bioengineering, Clemson University, Clemson, SC, USA.,Division of Urology, Department of Surgery, Duke University Medical Center, Durham, NC, USA.,Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
| | - Francis M Hughes
- Department of Bioengineering, Clemson University, Clemson, SC, USA.,Division of Urology, Department of Surgery, Duke University Medical Center, Durham, NC, USA
| | - Huixia Jin
- Division of Urology, Department of Surgery, Duke University Medical Center, Durham, NC, USA
| | - Jiro Nagatomi
- Department of Bioengineering, Clemson University, Clemson, SC, USA.
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26
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Kovács G, Környei Z, Tóth K, Baranyi M, Brunner J, Neubrandt M, Dénes Á, Sperlágh B. Modulation of P2X7 purinergic receptor activity by extracellular Zn 2+ in cultured mouse hippocampal astroglia. Cell Calcium 2018; 75:1-13. [PMID: 30098501 DOI: 10.1016/j.ceca.2018.07.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 07/05/2018] [Accepted: 07/28/2018] [Indexed: 02/06/2023]
Abstract
The P2X7R protein, a P2 type purinergic receptor functioning as a non-selective cation channel, is expressed in different cell types of the central nervous system in several regions of the brain. The activation of the P2X7R protein by ATP modulates excitatory neurotransmission and contributes to microglial activation, apoptosis and neuron-glia communication. Zinc is an essential micronutrient that is highly concentrated in the synaptic vesicles of glutamatergic hippocampal neurons where free zinc ions released into the synaptic cleft alter glutamatergic signal transmission. Changes in both P2X7R-mediated signaling and brain zinc homeostasis have been implicated in the pathogenesis of mood disorders. Here, we tested the hypothesis that extracellular zinc regulates P2X7R activity in the hippocampus. We observed that P2X7R is expressed in both neurons and glial cells in primary mouse hippocampal neuron-glia culture. Propidium iodide (PI) uptake through large pores formed by pannexins and P2X7R was dose-dependently inhibited by extracellular zinc ions. Calcium influx mediated by P2X7R in glial cells was also reduced by free zinc ions. Interestingly, no calcium influx was detected in response to ATP or 3'-O-(4-Benzoyl) benzoyl ATP (BzATP) in neurons despite the expression of P2X7R at the plasma membrane. Our results show that free zinc ions can modulate hippocampal glial purinergic signaling, and changes in the activity of P2X7R may contribute to the development of depression-like behaviors associated with zinc deficiency.
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Affiliation(s)
- Gergely Kovács
- Department of Pharmacology, Institute of Experimental Medicine of the Hungarian Academy of Sciences, Szigony utca 43, HU-1083 Budapest, Hungary; Szentágothai Research Centre, Institute of Physiology, Medical School, University of Pécs, 7624 Ifjúság útja 20, Pécs, Hungary.
| | - Zsuzsanna Környei
- Laboratory of Neuroimmunology, Institute of Experimental Medicine of the Hungarian Academy of Sciences, Szigony utca 43, Budapest, HU-1083 Hungary
| | - Krisztina Tóth
- Laboratory of Neuroimmunology, Institute of Experimental Medicine of the Hungarian Academy of Sciences, Szigony utca 43, Budapest, HU-1083 Hungary
| | - Mária Baranyi
- Department of Pharmacology, Institute of Experimental Medicine of the Hungarian Academy of Sciences, Szigony utca 43, HU-1083 Budapest, Hungary
| | - János Brunner
- Laboratory of Cellular Neuropharmacology, Institute of Experimental Medicine of the Hungarian Academy of Sciences, Szigony utca 43, HU-1083 Budapest, Hungary
| | - Máté Neubrandt
- Laboratory of Cellular Neuropharmacology, Institute of Experimental Medicine of the Hungarian Academy of Sciences, Szigony utca 43, HU-1083 Budapest, Hungary
| | - Ádám Dénes
- Laboratory of Neuroimmunology, Institute of Experimental Medicine of the Hungarian Academy of Sciences, Szigony utca 43, Budapest, HU-1083 Hungary
| | - Beáta Sperlágh
- Department of Pharmacology, Institute of Experimental Medicine of the Hungarian Academy of Sciences, Szigony utca 43, HU-1083 Budapest, Hungary
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27
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Schneider M, Prudic K, Pippel A, Klapperstück M, Braam U, Müller CE, Schmalzing G, Markwardt F. Interaction of Purinergic P2X4 and P2X7 Receptor Subunits. Front Pharmacol 2017; 8:860. [PMID: 29213241 PMCID: PMC5702805 DOI: 10.3389/fphar.2017.00860] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 11/09/2017] [Indexed: 11/13/2022] Open
Abstract
P2X4 and P2X7 are members of the P2X receptor family, comprising seven isoforms (P2X1–P2X7) that form homo- and heterotrimeric non-specific cation channels gated by extracellular ATP. P2X4 and P2X7 are widely coexpressed, particularly in secretory epithelial cells and immune and inflammatory cells, and regulate inflammation and nociception. Although functional heteromerization has been established for P2X2 and P2X3 subunits expressed in sensory neurons, there are contradictory reports regarding a functional interaction between P2X4 and P2X7 subunits. To resolve this issue, we coexpressed P2X4 and P2X7 receptor subunits labeled with green (EGFP) and red (TagRFP) fluorescent proteins in Xenopus laevis oocytes and investigated a putative physical interaction between the fusion proteins by Förster resonance energy transfer (FRET). Coexpression of P2X4 and P2X7 subunits with EGFP and TagRFP located in the extracellular receptor domains led to significant FRET signals. Significant FRET signals were also measured between C-terminally fluorophore-labeled full-length P2X41-384 and C-terminally truncated fluorescent P2X71-408 subunits. We furthermore used the two-electrode voltage clamp technique to investigate whether human P2X4 and P2X7 receptors (hP2X4, hP2X7) functionally interact at the level of ATP-induced whole-cell currents. Concentration–response curves and effects of ivermectin (P2X4-potentiating drug) or BzATP (P2X7-specific agonist) were consistent with a model in which coexpressed hP2X4 and hP2X7 do not interact. Similarly, the effect of adding specific inhibitors of P2X4 (PSB-15417) or P2X7 (oATP, A438079) could be explained by a model in which only homomers exist, and that these are blocked by the respective antagonist. In conclusion, we show that P2X4 and P2X7 subunits can form heterotrimeric P2X4/P2X7 receptors. However, unlike observations for P2X2 and P2X3, coexpression of P2X4 and P2X7 subunits does not result in a novel electrophysiologically discriminable P2X receptor phenotype.
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Affiliation(s)
- Markus Schneider
- Julius-Bernstein-Institute for Physiology, Martin-Luther-University, Halle, Germany
| | - Kirsten Prudic
- Julius-Bernstein-Institute for Physiology, Martin-Luther-University, Halle, Germany
| | - Anja Pippel
- Julius-Bernstein-Institute for Physiology, Martin-Luther-University, Halle, Germany
| | - Manuela Klapperstück
- Julius-Bernstein-Institute for Physiology, Martin-Luther-University, Halle, Germany
| | - Ursula Braam
- Molecular Pharmacology, RWTH Aachen University, Aachen, Germany
| | - Christa E Müller
- Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, Bonn, Germany
| | | | - Fritz Markwardt
- Julius-Bernstein-Institute for Physiology, Martin-Luther-University, Halle, Germany
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28
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Metzger MW, Walser SM, Aprile-Garcia F, Dedic N, Chen A, Holsboer F, Arzt E, Wurst W, Deussing JM. Genetically dissecting P2rx7 expression within the central nervous system using conditional humanized mice. Purinergic Signal 2017; 13:153-170. [PMID: 27858314 PMCID: PMC5432476 DOI: 10.1007/s11302-016-9546-z] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 10/26/2016] [Indexed: 12/16/2022] Open
Abstract
The purinergic P2X7 receptor (P2X7R) has attracted considerable interest as a potential target for various central nervous system (CNS) pathologies including affective and neurodegenerative disorders. To date, the distribution and cellular localization of the P2X7R in the brain are not fully resolved and a matter of debate mainly due to the limitations of existing tools. However, this knowledge should be a prerequisite for understanding the contribution of the P2X7R to brain disease. Here, we generated a genetic mouse model by humanizing the P2X7R in the mouse as mammalian model organism. We demonstrated its functionality and revealed species-specific characteristics of the humanized receptor, compared to the murine ortholog, regarding its receptivity to activation and modulation by 2',3'-O-(benzoyl-4-benzoyl)-adenosine 5'-triphosphate (BzATP) and trifluoperazine (TFP). This humanized P2rx7 allele is accessible to spatially and temporally controlled Cre recombinase-mediated inactivation. In contrast to previously generated knockout (KO) mice, none of the described P2rx7 splice variants evade this null allele. By selective disruption and assessment of human P2RX7 expression in different brain regions and cell types, we were able to demonstrate that the P2X7R is specifically expressed in glutamatergic pyramidal neurons of the hippocampus. Also, P2X7R is expressed in major non-neuronal lineages throughout the brain, i.e., astrocytes, oligodendrocytes, and microglia. In conclusion, this humanized mouse model provides the means for detailed assessment of human P2X7R function in vivo including evaluation of agonists or antagonists. In addition, this conditional allele will enable future loss-of-function studies in conjunction with mouse models for CNS disorders.
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Affiliation(s)
| | | | - Fernando Aprile-Garcia
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA)-CONICET- Partner Institute of the Max Planck Society, Buenos Aires, Argentina
- Max Planck Institute of Immunbiology and Epigenetics, 79108, Freiburg, Germany
| | - Nina Dedic
- Max Planck Institute of Psychiatry, 80804, Munich, Germany
| | - Alon Chen
- Max Planck Institute of Psychiatry, 80804, Munich, Germany
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Developmental Genetics, 85764, Neuherberg, Germany
| | - Florian Holsboer
- Max Planck Institute of Psychiatry, 80804, Munich, Germany
- HMNC Brain Health, 80539, Munich, Germany
| | - Eduardo Arzt
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA)-CONICET- Partner Institute of the Max Planck Society, Buenos Aires, Argentina
| | - Wolfgang Wurst
- German Center for Neurodegenerative Diseases (DZNE), Site Munich, 81377, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Adolf-Butenandt-Institut, Ludwig-Maximilians-Universität München, 80336, Munich, Germany
- Department of Neurobiology, Weizmann Institute of Science, 7610001, Rehovot, Israel
- Chair of Developmental Genetics c/o Helmholtz Zentrum München, Technische Universität München-Weihenstephan, 85764, Neuherberg, Germany
| | - Jan M Deussing
- Max Planck Institute of Psychiatry, 80804, Munich, Germany.
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29
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Stokes L, Layhadi JA, Bibic L, Dhuna K, Fountain SJ. P2X4 Receptor Function in the Nervous System and Current Breakthroughs in Pharmacology. Front Pharmacol 2017; 8:291. [PMID: 28588493 PMCID: PMC5441391 DOI: 10.3389/fphar.2017.00291] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 05/05/2017] [Indexed: 12/18/2022] Open
Abstract
Adenosine 5′-triphosphate is a well-known extracellular signaling molecule and neurotransmitter known to activate purinergic P2X receptors. Information has been elucidated about the structure and gating of P2X channels following the determination of the crystal structure of P2X4 (zebrafish), however, there is still much to discover regarding the role of this receptor in the central nervous system (CNS). In this review we provide an overview of what is known about P2X4 expression in the CNS and discuss evidence for pathophysiological roles in neuroinflammation and neuropathic pain. Recent advances in the development of pharmacological tools including selective antagonists (5-BDBD, PSB-12062, BX430) and positive modulators (ivermectin, avermectins, divalent cations) of P2X4 will be discussed.
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Affiliation(s)
- Leanne Stokes
- School of Pharmacy, University of East Anglia, Norwich Research ParkNorwich, United Kingdom.,School of Biomedical and Health Sciences, RMIT University, BundooraVIC, Australia
| | - Janice A Layhadi
- Biomedical Research Centre, School of Biological Sciences, University of East AngliaNorwich, United Kingdom
| | - Lucka Bibic
- School of Pharmacy, University of East Anglia, Norwich Research ParkNorwich, United Kingdom
| | - Kshitija Dhuna
- School of Biomedical and Health Sciences, RMIT University, BundooraVIC, Australia
| | - Samuel J Fountain
- Biomedical Research Centre, School of Biological Sciences, University of East AngliaNorwich, United Kingdom
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30
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Hetero-oligomerization between the TNF receptor superfamily members CD40, Fas and TRAILR2 modulate CD40 signalling. Cell Death Dis 2017; 8:e2601. [PMID: 28182009 PMCID: PMC5386471 DOI: 10.1038/cddis.2017.22] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 12/23/2016] [Accepted: 12/28/2016] [Indexed: 11/19/2022]
Abstract
TNF receptor superfamily members (TNFRSF) such as CD40, Fas and TRAIL receptor 2 (TRAILR2) participate to the adaptive immune response by eliciting survival, proliferation, differentiation and/or cell death signals. The balance between these signals determines the fate of the immune response. It was previously reported that these receptors are able to self-assemble in the absence of ligand through their extracellular regions. However, the role of this oligomerization is not well understood, and none of the proposed hypotheses take into account potential hetero-association of receptors. Using CD40 as bait in a flow cytometry Förster resonance energy transfer assay, TNFRSF members with known functions in B cells were probed for interactions. Both Fas and TRAILR2 associated with CD40. Immunoprecipitation experiments confirmed the interaction of CD40 with Fas at the endogenous levels in a BJAB B-cell lymphoma cell line deficient for TRAILR2. TRAILR2-expressing BJAB cells displayed a robust CD40–TRAILR2 interaction at the expense of the CD40–Fas interaction. The same results were obtained by proximity ligation assay, using TRAILR2-positive and -negative BJAB cells and primary human B cells. Expression of the extracellular domains of Fas or TRAILR2 with a glycolipid membrane anchor specifically reduced the intrinsic signalling pathway of CD40 in 293T cells. Conversely, BJAB cells lacking endogenous Fas or TRAILR2 showed an increased NF-κB response to CD40L. Finally, upregulation of TRAILR2 in primary human B cells correlated with reduced NF-κB activation and reduced proliferation in response to CD40L. Altogether, these data reveal that selective interactions between different TNFRSF members may modulate ligand-induced responses upstream signalling events.
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31
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Abstract
The P2X7 receptor is a trimeric ion channel gated by extracellular adenosine 5'-triphosphate. The receptor is present on an increasing number of different cells types including stem, blood, glial, neural, ocular, bone, dental, exocrine, endothelial, muscle, renal and skin cells. The P2X7 receptor induces various downstream events in a cell-specific manner, including inflammatory molecule release, cell proliferation and death, metabolic events, and phagocytosis. As such this receptor plays important roles in heath and disease. Increasing knowledge about the P2X7 receptor has been gained from studies of, but not limited to, protein chemistry including cloning, site-directed mutagenesis, crystal structures and atomic modeling, as well as from studies of primary tissues and transgenic mice. This chapter focuses on the P2X7 receptor itself. This includes the P2RX7 gene and its products including splice and polymorphic variants. This chapter also reviews modulators of P2X7 receptor activation and inhibition, as well as the transcriptional regulation of the P2RX7 gene via its promoter and enhancer regions, and by microRNA and long-coding RNA. Furthermore, this chapter discusses the post-translational modification of the P2X7 receptor by N-linked glycosylation, adenosine 5'-diphosphate ribosylation and palmitoylation. Finally, this chapter reviews interaction partners of the P2X7 receptor, and its cellular localisation and trafficking within cells.
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Affiliation(s)
- Ronald Sluyter
- School of Biological Sciences, University of Wollongong, Wollongong, NSW, 2522, Australia. .,Centre for Medical and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia. .,Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia.
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32
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Menzies RI, Tam FW, Unwin RJ, Bailey MA. Purinergic signaling in kidney disease. Kidney Int 2016; 91:315-323. [PMID: 27780585 DOI: 10.1016/j.kint.2016.08.029] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 08/10/2016] [Accepted: 08/15/2016] [Indexed: 02/04/2023]
Abstract
Nucleotides are key subunits for nucleic acids and provide energy for intracellular metabolism. They can also be released from cells to act physiologically as extracellular messengers or pathologically as danger signals. Extracellular nucleotides stimulate membrane receptors in the P2 and P1 family. P2X are ATP-activated cation channels; P2Y and P1 are G-protein coupled receptors activated by ATP, ADP, UTP, and UDP in the case of P2 or adenosine for P1. Renal P2 receptors influence both vascular contractility and tubular function. Renal cells also express ectonucleotidases that rapidly hydrolyze extracellular nucleotides. These enzymes integrate this multireceptor purinergic-signaling complex by determining the nucleotide milieu to titrate receptor activation. Purinergic signaling also regulates immune cell function by modulating the synthesis and release of various cytokines such as IL1-β and IL-18 as part of inflammasome activation. Abnormal or excessive stimulation of this intricate paracrine system can be pro- or anti-inflammatory, and is also linked to necrosis and apoptosis. Kidney tissue injury causes a localized increase in ATP concentration, and sustained activation of P2 receptors can lead to renal glomerular, tubular, and vascular cell damage. Purinergic receptors also regulate the activity and proliferation of fibroblasts, promoting both inflammation and fibrosis in chronic disease. In this short review we summarize some of the recent findings related to purinergic signaling in the kidney. We focus predominantly on the P2X7 receptor, discussing why antagonists have so far disappointed in clinical trials and how advances in our understanding of purinergic signaling might help to reposition these compounds as potential treatments for renal disease.
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Affiliation(s)
- Robert I Menzies
- British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, Scotland, UK
| | - Frederick W Tam
- Imperial College Renal and Transplant Centre, Department of Medicine, Imperial College London, UK
| | - Robert J Unwin
- Cardiovascular and Metabolic Diseases Biotech Unit, AstraZeneca Gothenburg, Sweden; UCL Centre for Nephrology, University College London, London, UK.
| | - Matthew A Bailey
- British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, Scotland, UK
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33
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Davis CJ, Taishi P, Honn KA, Koberstein JN, Krueger JM. P2X7 receptors in body temperature, locomotor activity, and brain mRNA and lncRNA responses to sleep deprivation. Am J Physiol Regul Integr Comp Physiol 2016; 311:R1004-R1012. [PMID: 27707719 DOI: 10.1152/ajpregu.00167.2016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 09/30/2016] [Accepted: 09/30/2016] [Indexed: 12/17/2022]
Abstract
The ionotropic purine type 2X7 receptor (P2X7R) is a nonspecific cation channel implicated in sleep regulation and brain cytokine release. Many endogenous rhythms covary with sleep, including locomotor activity and core body temperature. Furthermore, brain-hypothalamic cytokines and purines play a role in the regulation of these physiological parameters as well as sleep. We hypothesized that these parameters are also affected by the absence of the P2X7 receptor. Herein, we determine spontaneous expression of body temperature and locomotor activity in wild-type (WT) and P2X7R knockout (KO) mice and how they are affected by sleep deprivation (SD). We also compare hypothalamic, hippocampal, and cortical cytokine- and purine-related receptor and enzyme mRNA expressions before and after SD in WT and P2X7RKO mice. Next, in a hypothesis-generating survey of hypothalamic long noncoding (lnc) RNAs, we compare lncRNA expression levels between strains and after SD. During baseline conditions, P2X7RKO mice had attenuated temperature rhythms compared with WT mice, although locomotor activity patterns were similar in both strains. After 6 h of SD, body temperature and locomotion were enhanced to a greater extent in P2X7RKO mice than in WT mice during the initial 2-3 h after SD. Baseline mRNA levels of cortical TNF-α and P2X4R were higher in the KO mice than WT mice. In response to SD, the KO mice failed to increase hypothalamic adenosine deaminase and P2X4R mRNAs. Further, hypothalamic lncRNA expressions varied by strain, and with SD. Current data are consistent with a role for the P2X7R in thermoregulation and lncRNA involvement in purinergic signaling.
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Affiliation(s)
- Christopher J Davis
- Elson S. Floyd College of Medicine, Department of Biomedical Sciences, Washington State University-Spokane, Spokane, Washington; .,Sleep and Performance Research Center, Washington State University-Spokane, Spokane, Washington.,Program in Neuroscience, Washington State University-Spokane, Spokane, Washington; and
| | - Ping Taishi
- Elson S. Floyd College of Medicine, Department of Biomedical Sciences, Washington State University-Spokane, Spokane, Washington
| | - Kimberly A Honn
- Elson S. Floyd College of Medicine, Department of Biomedical Sciences, Washington State University-Spokane, Spokane, Washington.,Sleep and Performance Research Center, Washington State University-Spokane, Spokane, Washington.,Elson S. Floyd College of Medicine, Department of Medical Education and Clinical Sciences, Washington State University-Spokane, Spokane, Washington
| | - John N Koberstein
- Elson S. Floyd College of Medicine, Department of Biomedical Sciences, Washington State University-Spokane, Spokane, Washington
| | - James M Krueger
- Elson S. Floyd College of Medicine, Department of Biomedical Sciences, Washington State University-Spokane, Spokane, Washington.,Program in Neuroscience, Washington State University-Spokane, Spokane, Washington; and
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34
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Aprile-Garcia F, Metzger MW, Paez-Pereda M, Stadler H, Acuña M, Liberman AC, Senin SA, Gerez J, Hoijman E, Refojo D, Mitkovski M, Panhuysen M, Stühmer W, Holsboer F, Deussing JM, Arzt E. Co-Expression of Wild-Type P2X7R with Gln460Arg Variant Alters Receptor Function. PLoS One 2016; 11:e0151862. [PMID: 26986975 PMCID: PMC4795689 DOI: 10.1371/journal.pone.0151862] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 03/04/2016] [Indexed: 01/04/2023] Open
Abstract
The P2X7 receptor is a member of the P2X family of ligand-gated ion channels. A single-nucleotide polymorphism leading to a glutamine (Gln) by arginine (Arg) substitution at codon 460 of the purinergic P2X7 receptor (P2X7R) has been associated with mood disorders. No change in function (loss or gain) has been described for this SNP so far. Here we show that although the P2X7R-Gln460Arg variant per se is not compromised in its function, co-expression of wild-type P2X7R with P2X7R-Gln460Arg impairs receptor function with respect to calcium influx, channel currents and intracellular signaling in vitro. Moreover, co-immunoprecipitation and FRET studies show that the P2X7R-Gln460Arg variant physically interacts with P2X7R-WT. Specific silencing of either the normal or polymorphic variant rescues the heterozygous loss of function phenotype and restores normal function. The described loss of function due to co-expression, unique for mutations in the P2RX7 gene so far, explains the mechanism by which the P2X7R-Gln460Arg variant affects the normal function of the channel and may represent a mechanism of action for other mutations.
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Affiliation(s)
- Fernando Aprile-Garcia
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA)-CONICET- Partner Institute of the Max Planck Society, Buenos Aires, Argentina
- Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | | | | | | | - Matías Acuña
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA)-CONICET- Partner Institute of the Max Planck Society, Buenos Aires, Argentina
| | - Ana C. Liberman
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA)-CONICET- Partner Institute of the Max Planck Society, Buenos Aires, Argentina
| | - Sergio A. Senin
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA)-CONICET- Partner Institute of the Max Planck Society, Buenos Aires, Argentina
| | - Juan Gerez
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA)-CONICET- Partner Institute of the Max Planck Society, Buenos Aires, Argentina
| | - Esteban Hoijman
- Centro de Microscopías Avanzadas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Damian Refojo
- Max Planck Institute of Psychiatry, 80804, Munich, Germany
| | - Mišo Mitkovski
- Max Planck Institute of Experimental Medicine, 37075, Göttingen, Germany
| | | | - Walter Stühmer
- Max Planck Institute of Experimental Medicine, 37075, Göttingen, Germany
| | - Florian Holsboer
- Max Planck Institute of Psychiatry, 80804, Munich, Germany
- HMNC Brain Health, Munich, Germany
| | | | - Eduardo Arzt
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA)-CONICET- Partner Institute of the Max Planck Society, Buenos Aires, Argentina
- Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Max Planck Institute of Psychiatry, 80804, Munich, Germany
- * E-mail:
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35
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Burnstock G. P2X ion channel receptors and inflammation. Purinergic Signal 2016; 12:59-67. [PMID: 26739702 DOI: 10.1007/s11302-015-9493-0] [Citation(s) in RCA: 159] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 12/23/2015] [Indexed: 12/20/2022] Open
Abstract
Neuroinflammation limits tissue damage in response to pathogens or injury and promotes repair. There are two stages of inflammation, initiation and resolution. P2X receptors are gaining attention in relation to immunology and inflammation. The P2X7 receptor in particular appears to be an essential immunomodulatory receptor, although P2X1 and P2X4 receptors also appear to be involved. ATP released from damaged or infected cells causes inflammation by release of inflammatory cytokines via P2X7 receptors and acts as a danger signal by occupying upregulated P2X receptors on immune cells to increase immune responses. The purinergic involvement in inflammation is being explored for the development of novel therapeutic strategies.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK. .,Department of Pharmacology and Therapeutics, The University of Melbourne, Melbourne, Australia.
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Pérez-Flores G, Lévesque SA, Pacheco J, Vaca L, Lacroix S, Pérez-Cornejo P, Arreola J. The P2X7/P2X4 interaction shapes the purinergic response in murine macrophages. Biochem Biophys Res Commun 2015; 467:484-90. [DOI: 10.1016/j.bbrc.2015.10.025] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2015] [Accepted: 10/05/2015] [Indexed: 01/01/2023]
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Kowalski M, Hausmann R, Schmid J, Dopychai A, Stephan G, Tang Y, Schmalzing G, Illes P, Rubini P. Flexible subunit stoichiometry of functional human P2X2/3 heteromeric receptors. Neuropharmacology 2015; 99:115-30. [PMID: 26184350 DOI: 10.1016/j.neuropharm.2015.07.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 07/01/2015] [Accepted: 07/09/2015] [Indexed: 11/27/2022]
Abstract
The aim of the present work was to clarify whether heterotrimeric P2X2/3 receptors have a fixed subunit stoichiometry consisting of one P2X2 and two P2X3 subunits as previously suggested, or a flexible stoichiometry containing also the inverse subunit composition. For this purpose we transfected HEK293 cells with P2X2 and P2X3 encoding cDNA at the ratios of 1:2 and 4:1, and analysed the biophysical and pharmacological properties of the generated receptors by means of the whole-cell patch-clamp technique. The concentration-response curves for the selective agonist α,β-meATP did not differ from each other under the two transfection ratios. However, co-expression of an inactive P2X2 mutant and the wild type P2X3 subunit and vice versa resulted in characteristic distortions of the α,β-meATP concentration-response relationships, depending on which subunit was expressed in excess, suggesting that HEK293 cells express mixtures of (P2X2)1/(P2X3)2 and (P2X2)2/(P2X3)1 receptors. Whereas the allosteric modulators H+ and Zn2+ failed to discriminate between the two possible heterotrimeric receptor variants, the α,β-meATP-induced responses were blocked more potently by the competitive antagonist A317491, when the P2X2 subunit was expressed in deficit of the P2X3 subunit. Furthermore, blue-native PAGE analysis of P2X2 and P2X3 subunits co-expressed in Xenopus laevis oocytes and HEK293 cells revealed that plasma membrane-bound P2X2/3 receptors appeared in two clearly distinct heterotrimeric complexes: a (P2X2-GFP)2/(P2X3)1 complex and a (P2X2-GFP)1/(P2X3)2 complex. These data strongly indicate that the stoichiometry of the heteromeric P2X2/3 receptor is not fixed, but determined in a permutational manner by the relative availability of P2X2 and P2X3 subunits.
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Affiliation(s)
- Maria Kowalski
- Rudolf-Boehm-Institute of Pharmacology and Toxicology, University of Leipzig, 04107 Leipzig, Germany
| | - Ralf Hausmann
- Molecular Pharmacology, RWTH Aachen University, 52074 Aachen, Germany
| | - Julia Schmid
- Rudolf-Boehm-Institute of Pharmacology and Toxicology, University of Leipzig, 04107 Leipzig, Germany
| | - Anke Dopychai
- Molecular Pharmacology, RWTH Aachen University, 52074 Aachen, Germany
| | - Gabriele Stephan
- Rudolf-Boehm-Institute of Pharmacology and Toxicology, University of Leipzig, 04107 Leipzig, Germany
| | - Yong Tang
- Acupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine, 610075 Chengdu, China
| | | | - Peter Illes
- Rudolf-Boehm-Institute of Pharmacology and Toxicology, University of Leipzig, 04107 Leipzig, Germany
| | - Patrizia Rubini
- Rudolf-Boehm-Institute of Pharmacology and Toxicology, University of Leipzig, 04107 Leipzig, Germany.
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Howarth AR, Conway BR, Bailey MA. Vascular and inflammatory actions of P2X receptors in renal injury. Auton Neurosci 2015; 191:135-40. [PMID: 25998687 DOI: 10.1016/j.autneu.2015.05.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
P2 purinergic receptors are activated by extracellular ATP and subserve a plethora of roles in the body, including metabolism, inflammation and neuronal signalling. This review focuses on renal purinergic receptors and how different roles that they play may contribute to renal dysfunction and the progression of chronic kidney disease. Numerous studies have linked P2 receptors, particularly the P2X4R and P2X7R subtypes, to kidney injury and damage. However, the mechanisms underlying this association are not fully defined. Several studies show that activation of P2X4R and particularly P2X7R can have a pro-inflammatory effect, causing or exacerbating damage to renal tissue. However, clinical trials aiming to utilise P2X7R antagonists to treat inflammatory disease have been unsuccessful, and it is possible that other mechanisms besides inflammation tie P2X7R activation to disease progression. In this context, purinergic signalling is also involved in the control of vascular tone and our recent studies suggest that activation of P2X4R/P2X7R causes renal vascular dysfunction and contributes to chronic kidney disease. This brief review aims to summarise the complementary inflammatory and vascular roles of P2X receptors in the kidney, with emphasis on the subtypes P2X4R and P27XR, and how each contributes to and presents therapeutic targets in the progression of chronic kidney disease.
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Affiliation(s)
- Amelia R Howarth
- British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom
| | - Bryan R Conway
- British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom
| | - Matthew A Bailey
- British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom.
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Ase AR, Honson NS, Zaghdane H, Pfeifer TA, Séguéla P. Identification and characterization of a selective allosteric antagonist of human P2X4 receptor channels. Mol Pharmacol 2015; 87:606-16. [PMID: 25597706 DOI: 10.1124/mol.114.096222] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
P2X4 is an ATP-gated nonselective cation channel highly permeable to calcium. There is increasing evidence that this homomeric purinoceptor, which is expressed in several neuronal and immune cell types, is involved in chronic pain and inflammation. The current paucity of unambiguous pharmacological tools available to interrogate or modulate P2X4 function led us to pursue the search for selective antagonists. In the high-throughput screen of a compound library, we identified the phenylurea BX430 (1-(2,6-dibromo-4-isopropyl-phenyl)-3-(3-pyridyl)urea, molecular weight = 413), with antagonist properties on human P2X4-mediated calcium uptake. Patch-clamp electrophysiology confirmed direct inhibition of P2X4 currents by extracellular BX430, with submicromolar potency (IC50 = 0.54 µM). BX430 is highly selective, having virtually no functional impact on all other P2X subtypes, namely, P2X1-P2X3, P2X5, and P2X7, at 10-100 times its IC50. Unexpected species differences were noticed, as BX430 is a potent antagonist of zebrafish P2X4 but has no effect on rat and mouse P2X4 orthologs. The concentration-response curve for ATP on human P2X4 in the presence of BX430 shows an insurmountable blockade, indicating a noncompetitive allosteric mechanism of action. Using a fluorescent dye uptake assay, we observed that BX430 also effectively suppresses ATP-evoked and ivermectin-potentiated membrane permeabilization induced by P2X4 pore dilation. Finally, in single-cell calcium imaging, we validated its selective inhibitory effects on native P2X4 channels at the surface of human THP-1 cells that were differentiated into macrophages. In summary, this ligand provides a novel molecular probe to assess the specific role of P2X4 in inflammatory and neuropathic conditions, where ATP signaling has been shown to be dysfunctional.
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Affiliation(s)
- Ariel R Ase
- Montreal Neurological Institute, Alan Edwards Centre for Research on Pain, Department of Neurology and Neurosurgery, McGill University, Montreal, Canada (A.R.A., P.S.); Screening Division, The Centre for Drug Research and Discovery, Vancouver, Canada (N.S.H., T.A.P.); and Zamboni Chemical Solutions, Department of Chemistry, McGill University, Montreal, Canada (H.Z.)
| | - Nicolette S Honson
- Montreal Neurological Institute, Alan Edwards Centre for Research on Pain, Department of Neurology and Neurosurgery, McGill University, Montreal, Canada (A.R.A., P.S.); Screening Division, The Centre for Drug Research and Discovery, Vancouver, Canada (N.S.H., T.A.P.); and Zamboni Chemical Solutions, Department of Chemistry, McGill University, Montreal, Canada (H.Z.)
| | - Helmi Zaghdane
- Montreal Neurological Institute, Alan Edwards Centre for Research on Pain, Department of Neurology and Neurosurgery, McGill University, Montreal, Canada (A.R.A., P.S.); Screening Division, The Centre for Drug Research and Discovery, Vancouver, Canada (N.S.H., T.A.P.); and Zamboni Chemical Solutions, Department of Chemistry, McGill University, Montreal, Canada (H.Z.)
| | - Tom A Pfeifer
- Montreal Neurological Institute, Alan Edwards Centre for Research on Pain, Department of Neurology and Neurosurgery, McGill University, Montreal, Canada (A.R.A., P.S.); Screening Division, The Centre for Drug Research and Discovery, Vancouver, Canada (N.S.H., T.A.P.); and Zamboni Chemical Solutions, Department of Chemistry, McGill University, Montreal, Canada (H.Z.)
| | - Philippe Séguéla
- Montreal Neurological Institute, Alan Edwards Centre for Research on Pain, Department of Neurology and Neurosurgery, McGill University, Montreal, Canada (A.R.A., P.S.); Screening Division, The Centre for Drug Research and Discovery, Vancouver, Canada (N.S.H., T.A.P.); and Zamboni Chemical Solutions, Department of Chemistry, McGill University, Montreal, Canada (H.Z.)
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40
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Sperlágh B, Illes P. P2X7 receptor: an emerging target in central nervous system diseases. Trends Pharmacol Sci 2014; 35:537-47. [PMID: 25223574 DOI: 10.1016/j.tips.2014.08.002] [Citation(s) in RCA: 297] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 08/07/2014] [Accepted: 08/14/2014] [Indexed: 12/19/2022]
Abstract
The ATP-sensitive homomeric P2X7 receptor (P2X7R) has received particular attention as a potential drug target because of its widespread involvement in inflammatory diseases as a key regulatory element of the inflammasome complex. However, it has only recently become evident that P2X7Rs also play a pivotal role in central nervous system (CNS) pathology. There is an explosion of data indicating that genetic deletion and pharmacological blockade of P2X7Rs alter responsiveness in animal models of neurological disorders, such as stroke, neurotrauma, epilepsy, neuropathic pain, multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), Alzheimer's disease, Parkinson's disease, and Huntington's disease. Moreover, recent studies suggest that P2X7Rs regulate the pathophysiology of psychiatric disorders, including mood disorders, implicating P2X7Rs as drug targets in a variety of CNS pathology.
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Affiliation(s)
- Beáta Sperlágh
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1450 Budapest, Hungary.
| | - Peter Illes
- Rudolf Boehm Institute of Pharmacology and Toxicology, University of Leipzig, D-04107 Leipzig, Germany
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Antonio LS, Stewart AP, Varanda WA, Edwardson JM. Identification of P2X2/P2X4/P2X6 heterotrimeric receptors using atomic force microscopy (AFM) imaging. FEBS Lett 2014; 588:2125-8. [PMID: 24815693 DOI: 10.1016/j.febslet.2014.04.048] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 04/22/2014] [Indexed: 10/25/2022]
Abstract
Seven P2X purinergic receptor subunits have been identified: P2X1-P2X7. The overlapping expression of P2X2, P2X4 and P2X6 subunits has been shown in different cell types, and functional analysis of P2X receptors in Leydig cells suggests that the three subunits might interact. Here, His6-tagged P2X2, HA-tagged P2X4 and FLAG-tagged P2X6 subunits were co-expressed in tsA 201 cells. After sequential co-immunoprecipitation using anti-HA and anti-FLAG beads, all three subunits were present, demonstrating their interaction. Atomic force microscopy (AFM) imaging revealed receptors that were specifically decorated by both an anti-His6 antibody and an anti-HA Fab fragment, indicating the presence of a P2X2/4/6 heterotrimer. To our knowledge, this is the first report of a P2X receptor containing three different subunits.
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Affiliation(s)
- Ligia S Antonio
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom; Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Andrew P Stewart
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
| | - Wamberto A Varanda
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - J Michael Edwardson
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom.
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Saul A, Hausmann R, Kless A, Nicke A. Heteromeric assembly of P2X subunits. Front Cell Neurosci 2013; 7:250. [PMID: 24391538 PMCID: PMC3866589 DOI: 10.3389/fncel.2013.00250] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 11/21/2013] [Indexed: 12/01/2022] Open
Abstract
Transcripts and/or proteins of P2X receptor (P2XR) subunits have been found in virtually all mammalian tissues. Generally more than one of the seven known P2X subunits have been identified in a given cell type. Six of the seven cloned P2X subunits can efficiently form functional homotrimeric ion channels in recombinant expression systems. This is in contrast to other ligand-gated ion channel families, such as the Cys-loop or glutamate receptors, where homomeric assemblies seem to represent the exception rather than the rule. P2XR mediated responses recorded from native tissues rarely match exactly the biophysical and pharmacological properties of heterologously expressed homomeric P2XRs. Heterotrimerization of P2X subunits is likely to account for this observed diversity. While the existence of heterotrimeric P2X2/3Rs and their role in physiological processes is well established, the composition of most other P2XR heteromers and/or the interplay between distinct trimeric receptor complexes in native tissues is not clear. After a description of P2XR assembly and the structure of the intersubunit ATP-binding site, this review summarizes the distribution of P2XR subunits in selected mammalian cell types and the biochemically and/or functionally characterized heteromeric P2XRs that have been observed upon heterologous co-expression of P2XR subunits. We further provide examples where the postulated heteromeric P2XRs have been suggested to occur in native tissues and an overview of the currently available pharmacological tools that have been used to discriminate between homo- and heteromeric P2XRs.
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Affiliation(s)
- Anika Saul
- Department of Molecular Biology of Neuronal Signals, Max Planck Institute for Experimental Medicine Göttingen, Germany
| | - Ralf Hausmann
- Molecular Pharmacology, RWTH Aachen University Aachen, Germany
| | - Achim Kless
- Department of Discovery Informatics, Grünenthal GmbH, Global Drug Discovery Aachen, Germany
| | - Annette Nicke
- Department of Molecular Biology of Neuronal Signals, Max Planck Institute for Experimental Medicine Göttingen, Germany
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Craigie E, Birch RE, Unwin RJ, Wildman SS. The relationship between P2X4 and P2X7: a physiologically important interaction? Front Physiol 2013; 4:216. [PMID: 23966951 PMCID: PMC3744038 DOI: 10.3389/fphys.2013.00216] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 07/27/2013] [Indexed: 11/24/2022] Open
Abstract
Purinergic signaling within the kidney is becoming an important focus in the study of renal health and disease. The effectors of ATP signaling, the P2Y and P2X receptors, are expressed to varying extents in and along the nephron. There are many studies demonstrating the importance of the P2Y2 receptor on kidney function, and other P2 receptors are now emerging as participants in renal regulation. The P2X4 receptor has been linked to epithelial sodium transport in the nephron and expression levels of the P2X7 receptor are up-regulated in certain pathophysiological states. P2X7 antagonism has been shown to ameliorate rodent models of DOCA salt-induced hypertension and P2X4 null mice are hypertensive. Interestingly, polymorphisms in the genetic loci of P2X4 and P2X7 have been linked to blood pressure variation in human studies. In addition to the increasing evidence linking these two P2X receptors to renal function and health, a number of studies link the two receptors in terms of physical associations between their subunits, demonstrated both in vitro and in vivo. This review will analyze the current literature regarding interactions between P2X4 and P2X7 and assess the potential impact of these with respect to renal function.
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Affiliation(s)
- Eilidh Craigie
- Centre for Nephrology, UCL Medical School, University College London London, UK
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Pharmacological insights into the role of P2X4 receptors in behavioural regulation: lessons from ivermectin. Int J Neuropsychopharmacol 2013; 16:1059-70. [PMID: 23174033 PMCID: PMC3593990 DOI: 10.1017/s1461145712000909] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Purinergic ionotropic P2X receptors are a family of cation-permeable channels that bind extracellular adenosine 5'-triphosphate. In particular, convergent lines of evidence have recently highlighted P2X(4) receptors as a potentially critical target in the regulation of multiple nervous and behavioural functions, including pain, neuroendocrine regulation and hippocampal plasticity. Nevertheless, the role of the P2X(4) receptor in behavioural organization remains poorly investigated. To study the effects of P2X(4) activation, we tested the acute effects of its potent positive allosteric modulator ivermectin (IVM, 2.5-10 mg/kg i.p.) on a broad set of paradigms capturing complementary aspects of perceptual, emotional and cognitive regulation in mice. In a novel open field, IVM did not induce significant changes in locomotor activity, but increased the time spent in the peripheral zone. In contrast, IVM produced anxiolytic-like effects in the elevated plus maze and marble burying tasks, as well as depression-like behaviours in the tail-suspension and forced swim tests. The agent induced no significant behavioural changes in the conditioned place preference test and in the novel object recognition task. Finally, the drug induced a dose-dependent decrease in sensorimotor gating, as assessed by pre-pulse inhibition (PPI) of the acoustic startle reflex. In P2X(4) knockout mice, the effects of IVM in the open field and elevated plus maze were similar to those observed in wild type mice; conversely, the drug significantly increased startle amplitude and failed to reduce PPI. Taken together, these results suggest that P2X(4) receptors may play a role in the regulation of sensorimotor gating.
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45
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P2X7 receptors at adult neural progenitor cells of the mouse subventricular zone. Neuropharmacology 2013; 73:122-37. [PMID: 23727220 DOI: 10.1016/j.neuropharm.2013.05.017] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 05/01/2013] [Accepted: 05/04/2013] [Indexed: 02/07/2023]
Abstract
Neurogenesis requires the balance between the proliferation of newly formed progenitor cells and subsequent death of surplus cells. RT-PCR and immunocytochemistry demonstrated the presence of P2X7 receptor mRNA and immunoreactivity in cultured neural progenitor cells (NPCs) prepared from the adult mouse subventricular zone (SVZ). Whole-cell patch-clamp recordings showed a marked potentiation of the inward current responses both to ATP and the prototypic P2X7 receptor agonist dibenzoyl-ATP (Bz-ATP) at low Ca(2+) and zero Mg(2+) concentrations in the bath medium. The Bz-ATP-induced currents reversed their polarity near 0 mV; in NPCs prepared from P2X7(-/-) mice, Bz-ATP failed to elicit membrane currents. The general P2X/P2Y receptor antagonist PPADS and the P2X7 selective antagonists Brilliant Blue G and A-438079 strongly depressed the effect of Bz-ATP. Long-lasting application of Bz-ATP induced an initial current, which slowly increased to a steady-state response. In combination with the determination of YO-PRO uptake, these experiments suggest the dilation of a receptor-channel and/or the recruitment of a dye-uptake pathway. Ca(2+)-imaging by means of Fura-2 revealed that in a Mg(2+)-deficient bath medium Bz-ATP causes [Ca(2+)](i) transients fully depending on the presence of external Ca(2+). The MTT test indicated a concentration-dependent decrease in cell viability by Bz-ATP treatment. Correspondingly, Bz-ATP led to an increase in active caspase 3 immunoreactivity, indicating a P2X7-controlled apoptosis. In acute SVZ brain slices of transgenic Tg(nestin/EGFP) mice, patch-clamp recordings identified P2X7 receptors at NPCs with pharmacological properties identical to those of their cultured counterparts. We suggest that the apoptotic/necrotic P2X7 receptors at NPCs may be of particular relevance during pathological conditions which lead to increased ATP release and thus could counterbalance the ensuing excessive cell proliferation.
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Key Words
- 2-MeSATP
- 2-methylthio ATP
- 2′(3′)-O-(4-benzoylbenzoyl)adenosine-5′-triphosphate
- 2′,3′-O-(2,4,6-trinitrophenyl) adenosine 5′-triphosphate
- 3-(4,5-dimethylthioazol-2-yl)-2,5-diphenyltetrazoliumbromid
- 5-(3-bromophenyl)-1,3-dihydro-2H-benzofuro[3,2-e]-1,4-diazepin-2-one
- 5-BDBD
- Adult neural progenitor cells
- BBG
- Brain subventricular zone
- Brilliant Blue G
- Bz-ATP
- CNS
- E(max)
- EC(50)
- EGF
- Extracellular ATP
- FGF-2
- GAPDH
- GFAP
- MTT
- Msi1
- NPC
- P2X7 receptors
- PPADS
- SVZ
- TNP-ATP
- X(2) concentration
- [Ca(2+)](i)
- central nervous system
- concentration of agonist producing 50% of E(max)
- divalent cation concentration
- epidermal growth factor
- fibroblast growth factor-2
- glial fibrillary acidic protein
- glyceraldehyde 3-phosphate dehydrogenase
- intracellular Ca(2+) concentration
- maximal effect
- musashi1
- neural progenitor cell
- pyridoxalphosphate-6-azophenyl-2′,4′-disulfonic acid
- subventricular zone
- wild-type
- wt
- α,β-meATP
- α,β-methylene ATP
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46
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Nieto-Pescador MG, Guerrero-Alba R, Valdez-Morales E, Espinosa-Luna R, Jiménez-Vargas N, Liñan-Rico Andrómeda A, Ramos-Lomas TL, Díaz-Hernández Verónica V, Montaño LM, Barajas-López C. P2X4 subunits are part of P2X native channels in murine myenteric neurons. Eur J Pharmacol 2013; 709:93-102. [PMID: 23567069 DOI: 10.1016/j.ejphar.2013.03.045] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 03/27/2013] [Accepted: 03/28/2013] [Indexed: 02/06/2023]
Abstract
The aim of the present study was to investigate if P2X4 receptors are expressed in murine myenteric neurons and if these receptors contribute to form functional channels in the neuronal membrane by using molecular and electrophysiological techniques. The whole-cell recording technique was used to measure membrane currents induced by ATP (I(ATP)) in myenteric neurons. Compared with recombinant P2X4 receptor-channels (reported by others in a previous study), native myenteric P2X receptors have a relative lower sensitivity for ATP (EC₅₀=102 µM) and α,β methylene ATP (not effect at 30 or 100 µM). BzATP was a weak agonist for native P2X receptors. KN-62 had no effect on myenteric P2X channels whereas PPADS (IC₅₀=0.54 µM) or suramin (IC₅₀=134 µM) were more potent antagonists than on P2X4 homomeric channels. I(ATP) were potentiated by ivermectin (effect that is specific on P2X4 receptors) and zinc. Western blotting shows the presence of P2X4 protein and RT-PCR the corresponding mRNA transcript in the small intestine. Immunoreactivity for P2X4 receptors was found in most myenteric neurons in culture. Single-cell RT-PCR shows the presence of P2X4 mRNA in 90% of myenteric neurons. Our results indicate that P2X4 receptors are expressed in the majority of myenteric neurons, contribute to the membrane currents activated by ATP, and because most properties of I(ATP) does not correspond to P2X4 homomeric channels it is proposed that P2X4 are forming heteromeric channels in these neurons. P2X4 subunits have a widespread distribution within the myenteric plexus and would be expected to play an important role in cell signaling.
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Affiliation(s)
- María G Nieto-Pescador
- División de Biología Molecular, Instituto Potosino de Investigación Científica y Tecnológica, San Luis Potosí, SLP 78216, Mexico
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47
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Gu BJ, Baird PN, Vessey KA, Skarratt KK, Fletcher EL, Fuller SJ, Richardson AJ, Guymer RH, Wiley JS. A rare functional haplotype of the
P2RX4
and
P2RX7
genes leads to loss of innate phagocytosis and confers increased risk of age‐related macular degeneration. FASEB J 2013; 27:1479-87. [DOI: 10.1096/fj.12-215368] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Ben J. Gu
- Florey Institute of Neuroscience and Mental HealthUniversity of MelbourneParkvilleVictoriaAustralia
| | - Paul N. Baird
- Centre for Eye Research AustraliaUniversity of MelbourneRoyal Victorian Eye and Ear HospitalEast MelbourneVictoriaAustralia
| | - Kirstan A. Vessey
- Department of Anatomy and NeuroscienceUniversity of MelbourneParkvilleVictoriaAustralia
| | - Kristen K. Skarratt
- Nepean Clinical SchoolUniversity of SydneyNepean HospitalPenrithNew South WalesAustralia
| | - Erica L. Fletcher
- Department of Anatomy and NeuroscienceUniversity of MelbourneParkvilleVictoriaAustralia
| | - Stephen J. Fuller
- Nepean Clinical SchoolUniversity of SydneyNepean HospitalPenrithNew South WalesAustralia
| | - Andrea J. Richardson
- Centre for Eye Research AustraliaUniversity of MelbourneRoyal Victorian Eye and Ear HospitalEast MelbourneVictoriaAustralia
| | - Robyn H. Guymer
- Centre for Eye Research AustraliaUniversity of MelbourneRoyal Victorian Eye and Ear HospitalEast MelbourneVictoriaAustralia
| | - James S. Wiley
- Florey Institute of Neuroscience and Mental HealthUniversity of MelbourneParkvilleVictoriaAustralia
- Nepean Clinical SchoolUniversity of SydneyNepean HospitalPenrithNew South WalesAustralia
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48
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Mutations that hamper dimerization of foot-and-mouth disease virus 3A protein are detrimental for infectivity. J Virol 2012; 86:11013-23. [PMID: 22787230 DOI: 10.1128/jvi.00580-12] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Foot-and-mouth disease virus (FMDV) nonstructural protein 3A plays important roles in virus replication, virulence, and host range. In other picornaviruses, homodimerization of 3A has been shown to be relevant for its biological activity. In this work, FMDV 3A homodimerization was evidenced by an in situ protein fluorescent ligation assay. A molecular model of the FMDV 3A protein, derived from the nuclear magnetic resonance (NMR) structure of the poliovirus 3A protein, predicted a hydrophobic interface spanning residues 25 to 44 as the main determinant for 3A dimerization. Replacements L38E and L41E, involving charge acquisition at residues predicted to contribute to the hydrophobic interface, reduced the dimerization signal in the protein ligation assay and prevented the detection of dimer/multimer species in both transiently expressed 3A proteins and in synthetic peptides reproducing the N terminus of 3A. These replacements also led to production of infective viruses that replaced the acidic residues introduced (E) by nonpolar amino acids, indicating that preservation of the hydrophobic interface is essential for virus replication. Replacements that favored (Q44R) or impaired (Q44D) the polar interactions predicted between residues Q44 and D32 did not abolish dimer formation of transiently expressed 3A, indicating that these interactions are not critical for 3A dimerization. Nevertheless, while Q44R led to recovery of viruses that maintained the mutation, Q44D resulted in selection of infective viruses with substitution D44E with acidic charge but with structural features similar to those of the parental virus, suggesting that Q44 is involved in functions other than 3A dimerization.
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49
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Abstract
Ligand-gated ion channels are prototypic oligomeric membrane proteins whose stoichiometry determines their functional properties and subcellular localization. Deciphering the quaternary structure of such protein complexes is an arduous task and usually requires the combination of multiple approaches. ATP-gated P2X receptors are formed by the association of three subunits, but the quaternary arrangement of the seven P2X subunits at the plasma membrane remains poorly characterized. By combining bioluminescence resonance energy transfer, bifunctional fluorescence complementation and protein biochemistry, we developed an experimental approach that allows precise determination of rat P2X receptor quaternary assembly. We found that P2X5 subunits associate with P2X1, P2X2, and P2X4 subunits. We demonstrate that P2X5 and P2X2 subunits interact to form as yet uncharacterized heteromeric receptors with alternate stoichiometries, both present at the plasma membrane. P2X2/5 receptors display functional properties such as pore dilatation, membrane blebbing, and phosphatidylserine exposure that were previously thought to be characteristic hallmarks of the P2X7 receptor. In mouse, P2X2 and P2X5 subunits colocalize and physically interact in specific neuronal populations suggesting that other P2X receptors might contribute to cellular responses typically attributed to P2X7 receptor.
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50
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Masin M, Young C, Lim K, Barnes SJ, Xu XJ, Marschall V, Brutkowski W, Mooney ER, Gorecki DC, Murrell-Lagnado R. Expression, assembly and function of novel C-terminal truncated variants of the mouse P2X7 receptor: re-evaluation of P2X7 knockouts. Br J Pharmacol 2012; 165:978-93. [PMID: 21838754 DOI: 10.1111/j.1476-5381.2011.01624.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Splice variants of P2X7 receptor transcripts contribute to the diversity of receptor-mediated responses. Here, we investigated expression and function of C-terminal truncated (ΔC) variants of the mP2X7 receptor, which are predicted to escape inactivation in one strain of P2X7(-/-) mice (Pfizer KO). EXPERIMENTAL APPROACH Expression in wild-type (WT) and Pfizer KO tissue was investigated by reverse transcription (RT)-PCR and Western blot analysis. ΔC variants were also cloned and expressed in HEK293 cells to investigate their assembly, trafficking and function. KEY RESULTS RT-PCR indicates expression of a ΔC splice variant in brain, salivary gland (SG) and spleen from WT and Pfizer KO mice. An additional ΔC hybrid transcript, containing sequences of P2X7 upstream of exon 12, part of exon 13 followed in-frame by the sequence of the vector used to disrupt the P2X7 gene, was also identified in the KO mice. By blue native (BN) PAGE analysis and the use of cross linking reagents followed by SDS-PAGE, P2X7 trimers, dimers and monomers were detected in the spleen and SG of Pfizer KO mice. The molecular mass was reduced compared with P2X7 in WT mice tissue, consistent with a ΔC variant. When expressed in HEK293 cells the ΔC variants were inefficiently trafficked to the cell surface and agonist-evoked whole cell currents were small. Co-expressed with P2X7A, the ΔC splice variant acted in a dominant negative fashion to inhibit function. CONCLUSIONS AND IMPLICATIONS Pfizer KO mice are not null for P2X7 receptor expression but express ΔC variants with reduced function.
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Affiliation(s)
- Marianela Masin
- Department of Pharmacology, University of Cambridge, Cambridge, UK
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