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Acuña-Castillo C, Escobar A, García-Gómez M, Bachelet VC, Huidobro-Toro JP, Sauma D, Barrera-Avalos C. P2X7 Receptor in Dendritic Cells and Macrophages: Implications in Antigen Presentation and T Lymphocyte Activation. Int J Mol Sci 2024; 25:2495. [PMID: 38473744 DOI: 10.3390/ijms25052495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 01/15/2024] [Accepted: 01/24/2024] [Indexed: 03/14/2024] Open
Abstract
The P2X7 receptor, a member of the P2X purinergic receptor family, is a non-selective ion channel. Over the years, it has been associated with various biological functions, from modulating to regulating inflammation. However, its emerging role in antigen presentation has captured the scientific community's attention. This function is essential for the immune system to identify and respond to external threats, such as pathogens and tumor cells, through T lymphocytes. New studies show that the P2X7 receptor is crucial for controlling how antigens are presented and how T cells are activated. These studies focus on antigen-presenting cells, like dendritic cells and macrophages. This review examines how the P2X7 receptor interferes with effective antigen presentation and activates T cells and discusses the fundamental mechanisms that can affect the immune response. Understanding these P2X7-mediated processes in great detail opens up exciting opportunities to create new immunological therapies.
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Affiliation(s)
- Claudio Acuña-Castillo
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago 9160000, Chile
- Centro de Biotecnología Acuícola, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago 9160000, Chile
| | - Alejandro Escobar
- Laboratorio Biología Celular y Molecular, Instituto de Investigación en Ciencias Odontológicas, Facultad de Odontología, Universidad de Chile, Santiago 8380000, Chile
| | - Moira García-Gómez
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago 7800003, Chile
| | - Vivienne C Bachelet
- Escuela de Medicina, Facultad de Ciencias Médicas, Universidad de Santiago de Chile, Santiago 9160000, Chile
| | - Juan Pablo Huidobro-Toro
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago 9160000, Chile
| | - Daniela Sauma
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago 7800003, Chile
- Centro Ciencia & Vida, Av. Del Valle Norte 725, Huechuraba 8580000, Chile
| | - Carlos Barrera-Avalos
- Centro de Biotecnología Acuícola, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago 9160000, Chile
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Zhu G, Dai B, Chen Z, He L, Guo J, Dan Y, Liang S, Li G. Effects of chronic lead exposure on the sympathoexcitatory response associated with the P2X7 receptor in rat superior cervical ganglia. Auton Neurosci 2019; 219:33-41. [DOI: 10.1016/j.autneu.2019.03.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 02/01/2019] [Accepted: 03/20/2019] [Indexed: 12/23/2022]
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The P2X 7 receptor in dorsal root ganglia is involved in HIV gp120-associated neuropathic pain. Brain Res Bull 2017; 135:25-32. [PMID: 28919433 DOI: 10.1016/j.brainresbull.2017.09.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Revised: 05/10/2017] [Accepted: 09/13/2017] [Indexed: 01/28/2023]
Abstract
Human immunodeficiency virus (HIV)-associated neuropathic pain is common, and studies have shown that HIV envelope glycoprotein 120 (gp120) can directly stimulate primary sensory afferent neurons causing hyperalgesia. The P2X7 receptor in the dorsal root ganglia (DRG) is involved in pain transmission and is closely related to the inflammatory and immune response. In this study, we aimed to explore the role of the P2X7 receptor in gp120-induced neuropathic pain using a rat model specific for this type of pain. The results showed that mechanical hyperalgesia, thermal hyperalgesia and P2X7 expression levels were increased in rats treated with gp120. The P2X7 antagonist, brilliant blue G (BBG), decreased hyperalgesia and P2X7 expression levels in rats treated with gp120. BBG also decreased IL-1β and TNF-α receptor expression and ERK1/2 phosphorylation levels and increased IL-10 expression in the gp120-treated rat DRG. In addition, P2X7 agonist (BzATP)-activated currents in DRG neurons cultured with gp120 were larger than those in control neurons, and the inhibitory effect of BBG on BzATP-induced currents in gp120-treated DRG neurons was larger than that in control neurons. Therefore, inhibition of the P2X7 receptor in rat DRG relieved gp120-induced mechanical hyperalgesia and thermal hyperalgesia.
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P2X7 Participates in Intracerebral Hemorrhage-Induced Secondary Brain Injury in Rats via MAPKs Signaling Pathways. Neurochem Res 2017; 42:2372-2383. [PMID: 28488233 DOI: 10.1007/s11064-017-2257-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 03/29/2017] [Accepted: 03/30/2017] [Indexed: 01/31/2023]
Abstract
This study aimed to study the role of P2X7 in intracerebral hemorrhage (ICH)-induced secondary brain injury (SBI) and the underlying mechanisms. An autologous blood injection was used to induce ICH model in Sprague-Dawley rats, and cultured primary rat cortical neurons were exposed to oxyhemoglobin to mimic ICH in vitro. siRNA interference and over-expression of P2X7, agonists and antagonists of P2X7, p38 MAPK and ERK were exploited. The protein levels were assessed using Western blotting and immunofluorescence staining. Terminal deoxynucleotidyl transferase dUTP nick end labeling staining and Fluoro-Jade B were conducted to detect apoptotic and degenerating neurons. The protein levels of P2X7, phosphorylated p38, ERK, active caspase-3 and NF-κB were significantly increased by ICH, which could be further increased by BzATP (P2X7 agonist) and reduced by BBG (P2X7 antagonist). And BzATP demonstrated a significant increase in cell death ratio and brain water content, while BBG led to a reverse results. In addition, Over- P2X7 increased the levels of P2X7, phosphorylated p38, ERK, active caspase-3 and NF-κB, and aggravated cell apoptosis, while si P2X7 resulted in opposite effects. Finally, the protein levels of phosphorylated P38 and active caspase 3 were decreased by BzATP plus Hydrochloride (p38 MAPK antagonist) and increased vy BBG plus Asiatic acid (p38 MAPK agonist), while the protein levels of phosphorylated ERK and NF-κB were decreased with BzATP plus Nimbolide (ERK antagonist) and increased with BBG plus Saikosaponin C (ERK agonist). This study demonstrates that inhibition of P2X7 could prevent ICH-induced SBI via MAPKs signaling pathway.
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Wang J, Liu S, Nie Y, Wu B, Wu Q, Song M, Tang M, Xiao L, Xu P, Tan X, Zhang L, Li G, Liang S, Zhang C. Activation of P2X7 receptors decreases the proliferation of murine luteal cells. Reprod Fertil Dev 2017; 27:1262-71. [PMID: 25782073 DOI: 10.1071/rd14381] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 02/09/2015] [Indexed: 12/14/2022] Open
Abstract
Extracellular ATP regulates cellular function in an autocrine or paracrine manner through activating purinergic signalling. Studies have shown that purinergic receptors were expressed in mammalian ovaries and they have been proposed as an intra-ovarian regulatory mechanism. P2X7 was expressed in porcine ovarian theca cells and murine and human ovarian surface epithelium and is involved in ATP-induced apoptotic cell death. However, the role of P2X7 in corpus luteum is still unclear. The aim of this study was to investigate the role of ATP signalling in murine luteal cells and the possible mechanism(s) involved. We found that P2X7 was highly expressed in murine small luteal cells. The agonists of P2X7, ATP and BzATP, inhibited the proliferation of luteal cells. P2X7 antagonist BBG reversed the inhibition induced by ATP and BzATP. Further studies showed that ATP and BzATP inhibited the expression of cell cycle regulators cyclinD2 and cyclinE2. ATP and BzATP also inhibited the p38-mitogen-activated protein kinase (MAPK) signalling pathway. These results reveal that P2X7 receptor activation is involved in corpus luteum formation and function.
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Affiliation(s)
- Jing Wang
- Department of Microbiology, School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Shuangmei Liu
- Department of Physiology, School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Yijun Nie
- The First Affiliated Hospital, School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Bing Wu
- Department of Physiology, School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Qin Wu
- Department of Physiology, School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Miaomiao Song
- Department of Physiology, School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Min Tang
- Department of Cell Biology, School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Li Xiao
- Department of Cell Biology, School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Ping Xu
- School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Ximin Tan
- School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Luyin Zhang
- School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Gang Li
- Department of Cell Biology, School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Shangdong Liang
- Department of Physiology, School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
| | - Chunping Zhang
- Department of Cell Biology, School of Medicine, Nanchang University, #461 Bayi Avenue, Nanchang, Jiangxi 330006, People's Republic of China
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Yi Z, Rao S, Ouyang S, Bai Y, Yang J, Ma Y, Han X, Wu B, Zou L, Jia T, Zhao S, Hu X, Lei Q, Gao Y, Liu S, Xu H, Zhang C, Liang S, Li G. A317491 relieved HIV gp120-associated neuropathic pain involved in P2X 3 receptor in dorsal root ganglia. Brain Res Bull 2017; 130:81-89. [PMID: 28065732 DOI: 10.1016/j.brainresbull.2017.01.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 12/21/2016] [Accepted: 01/02/2017] [Indexed: 11/16/2022]
Abstract
Glycoprotein 120 (gp120) is an HIV envelope glycoprotein. Gp120 can directly stimulate the primary sensory afferent neurons and cause hyperalgesia. The P2X3 receptor in dorsal root ganglia (DRG) is involved in the transmission of pain. In this study, we aimed to explore the role of the P2X3 receptor in gp120-induced neuropathic pain. Our data showed that mechanical and thermal hyperalgesia in rats treated with gp120 were increased compared to those in the control group. The expression levels of the P2X3 mRNA and protein in rats treated with gp120 were higher than those in the control group. The P2X3 antagonist A317491 decreased mechanical hyperalgesia and thermal hyperalgesia and the up-regulated expression levels of P2X3 mRNA and protein in rats treated with gp120. A317491 decreased ERK1/2 phosphorylation levels in the gp120-treated rat DRG. In addition, P2X3 agonist α,β-methylene ATP (α,β-meATP)-activated currents in DRG neurons cultured with gp120 were higher than those in control neurons. The inhibitory effect of A317491 on α,βme-ATP-induced currents in DRG neurons from the gp120-treated neurons was larger than that for control neurons. Molecular docking data showed that A317491 may be acted in the gp120 protein to inhibit the gp120 initiated the P2X3 activation, decrease the sensitizing DRG primary afferents and reduce the signal transmission of neuropathic pain in gp120-treated rats. Therefore, the inhibition of the P2X3 receptor in rat DRG neurons relieved gp120-induced mechanical hyperalgesia.
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Affiliation(s)
- Zhihua Yi
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, People's Republic of China; Nursing College, Medical College of Nanchang University, Nanchang, Jiangxi 330006, People's Republic of China
| | - Shenqiang Rao
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, People's Republic of China
| | - Shuai Ouyang
- Department of the First Clinical, Medical College of Nanchang University, Nanchang, Jiangxi 330006, People's Republic of China
| | - Yi Bai
- Department of the First Clinical, Medical College of Nanchang University, Nanchang, Jiangxi 330006, People's Republic of China
| | - Jinpu Yang
- Queen Mary School, Medical College of Nanchang University, Nanchang, Jiangxi 330006, People's Republic of China
| | - Yucheng Ma
- Queen Mary School, Medical College of Nanchang University, Nanchang, Jiangxi 330006, People's Republic of China
| | - Xinyao Han
- Department of the First Clinical, Medical College of Nanchang University, Nanchang, Jiangxi 330006, People's Republic of China
| | - Bing Wu
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, People's Republic of China
| | - Lifang Zou
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, People's Republic of China
| | - Tianyu Jia
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, People's Republic of China
| | - Shanhong Zhao
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, People's Republic of China
| | - Xiaju Hu
- Nursing College, Medical College of Nanchang University, Nanchang, Jiangxi 330006, People's Republic of China
| | - Qiongqiong Lei
- Nursing College, Medical College of Nanchang University, Nanchang, Jiangxi 330006, People's Republic of China
| | - Yun Gao
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, People's Republic of China
| | - Shuangmei Liu
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, People's Republic of China
| | - Hong Xu
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, People's Republic of China
| | - Chunping Zhang
- Department of Cell Biology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, People's Republic of China
| | - Shangdong Liang
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, People's Republic of China.
| | - Guilin Li
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, People's Republic of China.
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Puchałowicz K, Baranowska-Bosiacka I, Dziedziejko V, Chlubek D. Purinergic signaling and the functioning of the nervous system cells. Cell Mol Biol Lett 2016; 20:867-918. [PMID: 26618572 DOI: 10.1515/cmble-2015-0050] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 10/29/2015] [Indexed: 12/19/2022] Open
Abstract
Purinergic signaling in the nervous system has been the focus of a considerable number of studies since the 1970s. The P2X and P2Y receptors are involved in the initiation of purinergic signaling. They are very abundant in the central and peripheral nervous systems, where they are expressed on the surface of neurons and glial cells--microglia, astrocytes, oligodendrocytes and Schwann cells and the precursors of the latter two. Their ligands--extracellular nucleotides--are released in the physiological state by astrocytes and neurons forming synaptic connections, and are essential for the proper functioning of nervous system cells. Purinergic signaling plays a crucial role in neuromodulation, neurotransmission, myelination in the CNS and PNS, intercellular communication, the regulation of ramified microglia activity, the induction of the response to damaging agents, the modulation of synaptic activity and other glial cells by astrocytes, and the induction of astrogliosis. Understanding these mechanisms and the fact that P2 receptors and their ligands are involved in the pathogenesis of diseases of the nervous system may help in the design of drugs with different and more effective mechanisms of action.
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Pathological potential of astroglial purinergic receptors. ADVANCES IN NEUROBIOLOGY 2014; 11:213-56. [PMID: 25236731 DOI: 10.1007/978-3-319-08894-5_11] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Acute brain injury and neurodegenerative disorders may result in astroglial activation. Astrocytes are able to determine the progression and outcome of these neuropathologies in a beneficial or detrimental way. Nucleotides, e.g. adenosine 5'-triphosphate (ATP), released after acute or chronic neuronal injury, are important mediators of glial activation and astrogliosis.Acute injury may cause significant changes in ATP balance, resulting in (1) a decline of intracellular ATP levels and (2) an increase in extracellular ATP concentrations via efflux from the intracellular space. The released ATP may have trophic effects, but can also act as a proinflammatory mediator or cytotoxic factor, inducing necrosis/apoptosis as a universal "danger" signal. Furthermore, ATP, primarily released from astrocytes, is a means of communication between neurons, glial cells, and intracerebral blood vessels.Astrocytes express a heterogeneous battery of purinergic ionotropic and metabotropic receptors (P2XRs and P2YRs, respectively) to respond to extracellular nucleotides.In this chapter, we summarize the contemporary knowledge on the pathological potential of P2Rs in relation to changes of astrocytic functions, determined by distinct molecular signaling cascades, in a variety of diseases. We discuss specific aspects of reactive astrogliosis, with respect to the involvement of prominent receptor subtypes, such as the P2X7 and P2Y1/2Rs. Examples of purinergic signaling of microglia, oligodendrocytes, and blood vessels under pathophysiological conditions will also be presented.The understanding of the pathological potential of purinergic signaling in "controlling and fine-tuning" of astrocytic responses is important for identifying possible therapeutic principles to treat acute and chronic central nervous system diseases.
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Kong F, Liu S, Xu C, Liu J, Li G, Li G, Gao Y, Lin H, Tu G, Peng H, Qiu S, Fan B, Zhu Q, Yu S, Zheng C, Liang S. Electrophysiological studies of upregulated P2X7 receptors in rat superior cervical ganglia after myocardial ischemic injury. Neurochem Int 2013; 63:230-7. [DOI: 10.1016/j.neuint.2013.06.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2012] [Revised: 06/02/2013] [Accepted: 06/06/2013] [Indexed: 01/07/2023]
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Cervetto C, Alloisio S, Frattaroli D, Mazzotta MC, Milanese M, Gavazzo P, Passalacqua M, Nobile M, Maura G, Marcoli M. The P2X7 receptor as a route for non-exocytotic glutamate release: dependence on the carboxyl tail. J Neurochem 2013; 124:821-31. [PMID: 23293841 DOI: 10.1111/jnc.12143] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 12/24/2012] [Accepted: 01/03/2013] [Indexed: 11/28/2022]
Abstract
P2X7 receptors trigger Ca(2+) -dependent exocytotic glutamate release, but also function as a route for non-exocytotic glutamate release from neurons or astrocytes. To gain an insight into the mechanisms involving the P2X7 receptor as a direct pathway for glutamate release, we compared the behavior of a full-length rat P2X7 receptor, a truncated rat P2X7 receptor in which the carboxyl tail had been deleted, a rat P2X7 receptor with the 18-amino acid cysteine-rich motif of the carboxyl tail deleted, and a rat P2X2 receptor, all of which are expressed in HEK293 cells. We found that the P2X7 receptor function as a route for glutamate release was antagonized in a non-competitive way by extracellular Mg(2+) , did not require the recruitment of pore-forming molecules, and was dependent on the carboxyl tail. Indeed, the truncated P2X7 receptor and the P2X7 receptor with the deleted cysteine-rich motif both lost their function as a pathway for glutamate release, while still evoking intracellular Ca(2+) elevation. No glutamate efflux was observed through the P2X2 receptor. Notably, HEK293 cells (lacking the machinery for Ca(2+) -dependent exocytosis), when transfected with P2X7 receptors, appear to be a suitable model for investigating the P2X7 receptor as a route for non-exocytotic glutamate efflux.
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Franke H, Verkhratsky A, Burnstock G, Illes P. Pathophysiology of astroglial purinergic signalling. Purinergic Signal 2012; 8:629-57. [PMID: 22544529 DOI: 10.1007/s11302-012-9300-0] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 02/01/2012] [Indexed: 12/13/2022] Open
Abstract
Astrocytes are fundamental for central nervous system (CNS) physiology and are the fulcrum of neurological diseases. Astroglial cells control development of the nervous system, regulate synaptogenesis, maturation, maintenance and plasticity of synapses and are central for nervous system homeostasis. Astroglial reactions determine progression and outcome of many neuropathologies and are critical for regeneration and remodelling of neural circuits following trauma, stroke, ischaemia or neurodegenerative disorders. They secrete multiple neurotransmitters and neurohormones to communicate with neurones, microglia and the vascular walls of capillaries. Signalling through release of ATP is the most widespread mean of communication between astrocytes and other types of neural cells. ATP serves as a fast excitatory neurotransmitter and has pronounced long-term (trophic) roles in cell proliferation, growth, and development. During pathology, ATP is released from damaged cells and acts both as a cytotoxic factor and a proinflammatory mediator, being a universal "danger" signal. In this review, we summarise contemporary knowledge on the role of purinergic receptors (P2Rs) in a variety of diseases in relation to changes of astrocytic functions and nucleotide signalling. We have focussed on the role of the ionotropic P2X and metabotropic P2YRs working alone or in concert to modify the release of neurotransmitters, to activate signalling cascades and to change the expression levels of ion channels and protein kinases. All these effects are of great importance for the initiation, progression and maintenance of astrogliosis-the conserved and ubiquitous glial defensive reaction to CNS pathologies. We highlighted specific aspects of reactive astrogliosis, especially with respect to the involvement of the P2X(7) and P2Y(1)R subtypes. Reactive astrogliosis exerts both beneficial and detrimental effects in a context-specific manner determined by distinct molecular signalling cascades. Understanding the role of purinergic signalling in astrocytes is critical to identifying new therapeutic principles to treat acute and chronic neurological diseases.
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Affiliation(s)
- Heike Franke
- Rudolf Boehm Institute of Pharmacology and Toxicology, University of Leipzig, Härtelstrasse 16-18, 04107, Leipzig, Germany.
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Lipopolysaccharide inhibits the channel activity of the P2X7 receptor. Mediators Inflamm 2011; 2011:152625. [PMID: 21941410 PMCID: PMC3173735 DOI: 10.1155/2011/152625] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 06/03/2011] [Accepted: 06/20/2011] [Indexed: 11/29/2022] Open
Abstract
The purinergic P2X7 receptor (P2X7R) plays an important role during the immune response, participating in several events such as cytokine release, apoptosis, and necrosis. The bacterial endotoxin lipopolysaccharide (LPS) is one of the strongest stimuli of the immune response, and it has been shown that P2X7R activation can modulate LPS-induced responses. Moreover, a C-terminal binding site for LPS has been proposed. In order to evaluate if LPS can directly modulate the activity of the P2X7R, we tested several signaling pathways associated with P2X7R activation in HEK293 cells that do not express the TLR-4 receptor. We found that LPS alone was unable to induce any P2X7R-related activity, suggesting that the P2X7R is not directly activated by the endotoxin. On the other hand, preapplication of LPS inhibited ATP-induced currents, intracellular calcium increase, and ethidium bromide uptake and had no effect on ERK activation in HEK293 cells. In splenocytes-derived T-regulatory cells, in which ATP-induced apoptosis is driven by the P2X7R, LPS inhibited ATP-induced apoptosis. Altogether, these results demonstrate that LPS modulates the activity of the P2X7R and suggest that this effect could be of physiological relevance.
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Traini C, Pedata F, Cipriani S, Mello T, Galli A, Giovannini MG, Cerbai F, Volpini R, Cristalli G, Pugliese AM. P2 receptor antagonists prevent synaptic failure and extracellular signal-regulated kinase 1/2 activation induced by oxygen and glucose deprivation in rat CA1 hippocampus in vitro. Eur J Neurosci 2011; 33:2203-15. [PMID: 21453436 DOI: 10.1111/j.1460-9568.2011.07667.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
To investigate the role of purinergic P2 receptors under ischemia, we studied the effect of P2 receptor antagonists on synaptic transmission and mitogen-activated protein kinase (MAPK) activation under oxygen and glucose deprivation (OGD) in rat hippocampal slices. The effect of the P2 antagonists pyridoxalphosphate-6-azophenyl-2',4'-disulfonate (PPADS, unselective, 30 μm), N( 6) -methyl-2'-deoxyadenosine-3',5'-bisphosphate (MRS2179, selective for P2Y(1) receptor, 10 μm), Brilliant Blue G (BBG, selective for P2X(7) receptor, 1 μm), and 5-[[[(3-phenoxyphenyl)methyl][(1S)-1,2,3,4-tetrahydro-1-naphthalenyl]amino]carbonyl]-1,2,4-benzenetricarboxylic acid (A-317491, selective for P2X(3) receptor, 10 μm), and of the newly synthesized P2X(3) receptor antagonists 2-amino-9-(5-iodo-2-isopropyl-4-methoxybenzyl)adenine (PX21, 1 μm) and 2-amino-9-(5-iodo-2-isopropyl-4-methoxybenzyl)-N( 6)-methyladenine (PX24, 1 μm), on the depression of field excitatory postsynaptic potentials (fEPSPs) and anoxic depolarization (AD) elicited by 7 min of OGD were evaluated. All antagonists significantly prevented these effects. The extent of CA1 cell injury was assessed 3 h after the end of 7 min of OGD by propidium iodide staining. Substantial CA1 pyramidal neuronal damage, detected in untreated slices exposed to OGD injury, was significantly prevented by PPADS (30 μm), MRS2179 (10 μm), and BBG (1 μm). Western blot analysis showed that, 10 min after the end of the 7 min of OGD, extracellular signal-regulated kinase (ERK)1/2 MAPK activation was significantly increased. MRS2179, BBG, PPADS and A-317491 significantly counteracted ERK1/2 activation. Hippocampal slices incubated with the ERK1/2 inhibitors 1,4-diamino-2,3-dicyano-1,4-bis(2-aminophenylthio)butadiene (U0126, 10 μm) and α-[amino[(4-aminophenyl)thio]methylene]-2-(trifluoromethyl) benzeneacetonitrile (SL327, 10 μm) showed significant fEPSP recovery after OGD and delayed AD, supporting the involvement of ERK1/2 in neuronal damage induced by OGD. These results indicate that subtypes of hippocampal P2 purinergic receptors have a harmful effect on neurotransmission in the CA1 hippocampus by participating in AD appearance and activation of ERK1/2.
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Affiliation(s)
- Chiara Traini
- Department of Preclinical and Clinical Pharmacology, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy
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Ivison SM, Himmel ME, Mayer M, Yao Y, Kifayet A, Levings MK, Steiner TS. The stress signal extracellular ATP modulates antiflagellin immune responses in intestinal epithelial cells. Inflamm Bowel Dis 2011; 17:319-33. [PMID: 20722064 DOI: 10.1002/ibd.21428] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Accepted: 06/17/2010] [Indexed: 12/11/2022]
Abstract
BACKGROUND Although intestinal epithelial cells (IECs) are continually exposed to commensal microbes, under healthy conditions they contribute to intestinal homeostasis while keeping inflammatory responses in check. In response to invading pathogens, however, IECs respond vigorously by producing inflammatory mediators. To better understand the signals that regulate the inflammatory responses of IECs, we investigated whether the danger signal ATP (which is released from injured cells) could alter responses to bacterial products. METHODS We measured chemokine production from Caco-2 cells stimulated with the Toll-like receptor 5 agonist flagellin with or without ATP. ATP increased flagellin-induced IL-8 secretion but reduced CCL20 secretion via distinct signaling pathways. RESULTS ATP-enhanced IL-8 production was only partly blocked by the P(2) receptor antagonist suramin and required activation of NF-κB while ATP-mediated reduction of CCL20 was completely blocked by suramin and required activation of ERK1/2. The effects of ATP on both chemokines required extracellular calcium but not phospholipase C, implicating P(2) X receptor involvement. To investigate how ATP alters IEC responses to bacterial products in vivo, mice receiving dextran sodium sulfate were given intrarectal flagellin with or without ATP. Addition of ATP to flagellin caused greater weight loss and increased antiflagellin antibody titers, as well as decreased colonic interferon gamma (IFN-γ) and higher antiflagellin IgG1/IgG2 ratios, which indicate decreased Th1 polarization. CONCLUSIONS Together, these data indicate that stress, in the form of extracellular ATP, reshapes both the inflammatory response of flagellin-stimulated IECs and downstream adaptive immunity, representing a possible strategy by which these cells differentiate between commensal and pathogenic bacteria.
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Affiliation(s)
- Sabine M Ivison
- Division of Infectious Diseases, Department of Medicine, University of British Columbia, Vancouver, BC, Canada.
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Munoz L, Ammit AJ. Targeting p38 MAPK pathway for the treatment of Alzheimer's disease. Neuropharmacology 2009; 58:561-8. [PMID: 19951717 DOI: 10.1016/j.neuropharm.2009.11.010] [Citation(s) in RCA: 257] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Revised: 10/30/2009] [Accepted: 11/24/2009] [Indexed: 10/20/2022]
Abstract
Accumulating evidence indicates that p38 mitogen-activated protein kinase (MAPK) could play more than one role in Alzheimer's disease (AD) pathophysiology and that patients suffering from AD dementia could benefit from p38 MAPK inhibitors. The p38 MAPK signalling has been widely accepted as a cascade contributing to neuroinflammation. However, deepening insight into the underlying biology of Alzheimer's disease reveals that p38 MAPK operates in other events related to AD, such as excitotoxicity, synaptic plasticity and tau phosphorylation. Although quantification of behavioural improvements upon p38 MAPK inhibition and in vivo evaluation of p38 MAPK significance to various aspects of AD pathology is still missing, the p38 MAPK is emerging as a new Alzheimer's disease treatment strategy. Thus, we present here an update on the role of p38 MAPK in neurodegeneration, with a focus on Alzheimer's disease, by summarizing recent literature and several key papers from earlier years.
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Affiliation(s)
- Lenka Munoz
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, The University of Sydney, NSW 2006, Australia.
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Nagasawa K, Miyaki J, Kido Y, Higashi Y, Nishida K, Fujimoto S. Possible involvement of PPAR gamma in the regulation of basal channel opening of P2X7 receptor in cultured mouse astrocytes. Life Sci 2009; 84:825-31. [PMID: 19348833 DOI: 10.1016/j.lfs.2009.03.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Revised: 03/16/2009] [Accepted: 03/25/2009] [Indexed: 10/20/2022]
Abstract
AIMS Recently, we demonstrated that cultured mouse astrocytes exhibited basal channel opening of P2X7 receptor (P2X7R) in the absence of any exogenous ligand, but the regulatory mechanism involved was not elucidated. Since our preliminary experiments suggested possible involvement of peroxisome proliferator-activated receptor (PPAR) gamma in the regulation, we examined whether PPAR gamma regulated P2X7R basal channel opening in mouse astrocytes. MAIN METHODS P2X7R channel opening was assessed as to the uptake of a marker dye, YO-PRO-1 (YP), in the presence or absence of agonists and antagonists for PPAR gamma under a fluorescence microscope. Expression of PPAR gamma was evaluated by Western blotting and immunocytochemistry. KEY FINDINGS NSAIDs such as flufenamic acid (FFA) and indomethacin, which are a cyclooxygenase inhibitor and a PPAR gamma agonist, showed enhancing and inhibiting effects on YP uptake at low and high concentrations, respectively, and the enhanced uptake was abolished by periodate-oxidized ATP (oxATP), a selective P2X7R antagonist. The PPAR gamma agonists 15-deoxy-Delta(12,14)-prostaglandin J(2) and ciglitazone decreased the basal and FFA-enhanced YP uptake, while the antagonist GW9662 increased YP uptake, this effect being blocked by the agonists and also by oxATP. PPAR gamma was distributed in the nucleus and cytosolic/membrane fraction of cultured mouse astrocytes. SIGNIFICANCE These findings indicate that basal channel opening of P2X7R in mouse astrocytes is at least in part regulated by PPAR gamma.
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Affiliation(s)
- Kazuki Nagasawa
- Department of Environmental Biochemistry, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto 607-8414, Japan.
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Mao LM, Tang QS, Wang JQ. Regulation of extracellular signal-regulated kinase phosphorylation in cultured rat striatal neurons. Brain Res Bull 2009; 78:328-34. [PMID: 19056470 PMCID: PMC2736782 DOI: 10.1016/j.brainresbull.2008.11.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Revised: 11/05/2008] [Accepted: 11/06/2008] [Indexed: 11/20/2022]
Abstract
Recent studies demonstrate that activation of Ca(2+)-permeable N-methyl-D-aspartate (NMDA) receptors upregulates phosphorylation of mitogen-activated protein kinases (MAPKs) in heterologous cells and neurons. In cultured rat striatal neurons, the present work systematically evaluated the role of a number of protein kinases in forming a signaling cascade transducing NMDA receptor signals to MAPKs. It was found that a brief NMDA application consistently induced rapid and transient phosphorylation of the extracellular signal-regulated kinase 1/2 (ERK1/2), a best characterized subclass of MAPKs. This ERK1/2 phosphorylation was resistant to the inhibition of protein kinase C, p38 MAPK, cyclin-dependent kinase 5, receptor tyrosine kinase (epidermal growth factor receptors), or non-receptor tyrosine kinases (including Src) by their selective inhibitors. However, the increase in ERK1/2 phosphorylation was partially blocked by a protein kinase A (PKA) inhibitor. The inhibitors for Ca(2+)/calmodulin-dependent protein kinase (CaMK) or phosphatidylinositol 3-kinase (PI3-kinase) completely blocked the NMDA-stimulated ERK1/2 phosphorylation. In an attempt to characterize the sequential role of CaMK and PI3-kinase, we found that NMDA increased PI3-kinase phosphorylation on Tyr(508), which kinetically corresponded to the ERK1/2 phosphorylation and was blocked by the CaMK inhibitor. These results indicate that the protein kinases are differentially involved in linking NMDA receptors to ERK1/2 in striatal neurons.
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Affiliation(s)
- Li-Min Mao
- Department of Basic Medical Science, School of Medicine, University of Missouri-Kansas City, Kansas City, MO 64108, USA.
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