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Wei C, Fu M, Zhang H, Yao B. How is the P2X7 receptor signaling pathway involved in epileptogenesis? Neurochem Int 2024; 173:105675. [PMID: 38211839 DOI: 10.1016/j.neuint.2024.105675] [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: 09/21/2023] [Revised: 12/22/2023] [Accepted: 01/03/2024] [Indexed: 01/13/2024]
Abstract
Epilepsy, a condition characterized by spontaneous recurrent epileptic seizures, is among the most prevalent neurological disorders. This disorder is estimated to affect approximately 70 million people worldwide. Although antiseizure medications are considered the first-line treatments for epilepsy, most of the available antiepileptic drugs are not effective in nearly one-third of patients. This calls for the development of more effective drugs. Evidence from animal models and epilepsy patients suggests that strategies that interfere with the P2X7 receptor by binding to adenosine triphosphate (ATP) are potential treatments for this patient population. This review describes the role of the P2X7 receptor signaling pathways in epileptogenesis. We highlight the genes, purinergic signaling, Pannexin1, glutamatergic signaling, adenosine kinase, calcium signaling, and inflammatory response factors involved in the process, and conclude with a synopsis of these key connections. By unraveling the intricate interplay between P2X7 receptors and epileptogenesis, this review provides ideas for designing potent clinical therapies that will revolutionize both prevention and treatment for epileptic patients.
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Affiliation(s)
- Caichuan Wei
- Department of Pediatrics, Renmin Hospital of Wuhan University, 99 Zhang Zhidong Road, Wuchang District, Wuhan, Hubei Province 430060, China
| | - Miaoying Fu
- Department of Pediatrics, Renmin Hospital of Wuhan University, 99 Zhang Zhidong Road, Wuchang District, Wuhan, Hubei Province 430060, China
| | - Haiju Zhang
- Department of Pediatrics, Renmin Hospital of Wuhan University, 99 Zhang Zhidong Road, Wuchang District, Wuhan, Hubei Province 430060, China
| | - Baozhen Yao
- Department of Pediatrics, Renmin Hospital of Wuhan University, 99 Zhang Zhidong Road, Wuchang District, Wuhan, Hubei Province 430060, China.
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Ahn YH, Tang Y, Illes P. The neuroinflammatory astrocytic P2X7 receptor: Alzheimer's disease, ischemic brain injury, and epileptic state. Expert Opin Ther Targets 2023; 27:763-778. [PMID: 37712394 DOI: 10.1080/14728222.2023.2258281] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 08/04/2023] [Accepted: 09/08/2023] [Indexed: 09/16/2023]
Abstract
INTRODUCTION Astrocytes have previously been considered as cells supporting neuronal functions, but they are now recognized as active players in maintaining central nervous system (CNS) homeostasis. Astrocytes can communicate with other CNS cells, i.e. through the gliotransmitter ATP and P2X7 receptors (Rs). AREAS COVERED In this review, we will discuss how the P2X7R initiates the release of gliotransmitters and proinflammatory cytokines/chemokines, thereby establishing a dialog between astrocytes and neurons and, in addition, causing neuroinflammation. In astrocytes, dysregulation of P2X7Rs has been associated with neurodegenerative illnesses such as Alzheimer's disease (AD), as well as the consequences of cerebral ischemic injury and status epilepticus (SE). EXPERT OPINION Although all CNS cells are possible sources of ATP release, the targets of this ATP are primarily at microglial cells. However, astrocytes also contain ATP-sensitive P2X7Rs and have in addition the peculiar property over microglia to continuously interact with neurons via not only inflammatory mediators but also gliotransmitters, such as adenosine 5'-triphosphate (ATP), glutamate, γ-amino butyric acid (GABA), and D-serine. Cellular damage arising during AD, cerebral ischemia, and SE via P2X7R activation is superimposed upon the original disease, and their prevention by blood-brain barrier permeable pharmacological antagonists is a valid therapeutic option.
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Affiliation(s)
- Young Ha Ahn
- International Joint Research Center on Purinergic Signaling of Sichuan Province, Chengdu University of TCM, Chengdu, China
| | - Yong Tang
- International Joint Research Center on Purinergic Signaling of Sichuan Province, Chengdu University of TCM, Chengdu, China
- School of Acupuncture and Tuina, Chengdu University of TCM, Chengdu, China
| | - Peter Illes
- International Joint Research Center on Purinergic Signaling of Sichuan Province, Chengdu University of TCM, Chengdu, China
- Rudolf Boehm Institute of Pharmacology and Toxicology, University of Leipzig, Leipzig, Germany
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3
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Aresta Branco MSL, Gutierrez Cruz A, Peri LE, Mutafova-Yambolieva VN. The Pannexin 1 Channel and the P2X7 Receptor Are in Complex Interplay to Regulate the Release of Soluble Ectonucleotidases in the Murine Bladder Lamina Propria. Int J Mol Sci 2023; 24:9964. [PMID: 37373111 PMCID: PMC10298213 DOI: 10.3390/ijms24129964] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 05/25/2023] [Accepted: 06/07/2023] [Indexed: 06/29/2023] Open
Abstract
The bladder urothelium releases ATP into the lamina propria (LP) during filling, which can activate P2X receptors on afferent neurons and trigger the micturition reflex. Effective ATP concentrations are largely dependent on metabolism by membrane-bound and soluble ectonucleotidases (s-ENTDs), and the latter are released in the LP in a mechanosensitive manner. Pannexin 1 (PANX1) channel and P2X7 receptor (P2X7R) participate in urothelial ATP release and are physically and functionally coupled, hence we investigated whether they modulate s-ENTDs release. Using ultrasensitive HPLC-FLD, we evaluated the degradation of 1,N6-etheno-ATP (eATP, substrate) to eADP, eAMP, and e-adenosine (e-ADO) in extraluminal solutions that were in contact with the LP of mouse detrusor-free bladders during filling prior to substrate addition, as an indirect measure of s-ENDTS release. Deletion of Panx1 increased the distention-induced, but not the spontaneous, release of s-ENTDs, whereas activation of P2X7R by BzATP or high concentration of ATP in WT bladders increased both. In Panx1-/- bladders or WT bladders treated with the PANX1 inhibitory peptide 10Panx, however, BzATP had no effect on s-ENTDS release, suggesting that P2X7R activity depends on PANX1 channel opening. We concluded, therefore, that P2X7R and PANX1 are in complex interaction to regulate s-ENTDs release and maintain suitable ATP concentrations in the LP. Thus, while stretch-activated PANX1 hinders s-ENTDS release possibly to preserve effective ATP concentration at the end of bladder filling, P2X7R activation, presumably in cystitis, would facilitate s-ENTDs-mediated ATP degradation to counteract excessive bladder excitability.
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Affiliation(s)
| | | | | | - Violeta N. Mutafova-Yambolieva
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada Reno, Reno, NV 89557, USA; (M.S.L.A.B.); (A.G.C.); (L.E.P.)
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Purohit R, Bera AK. Carboxyl terminus of Pannexin-1 plays a crucial role in P2X7 receptor-mediated signaling. Biochem Biophys Res Commun 2023; 664:20-26. [PMID: 37130457 DOI: 10.1016/j.bbrc.2023.04.081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 04/12/2023] [Accepted: 04/24/2023] [Indexed: 05/04/2023]
Abstract
The cellular implications of the interaction between Pannexin-1 (Panx1) channel and P2X7 receptor (P2X7R) have not been fully elucidated. Evidence suggests that ATP, released through Panx1, activates P2X7R, which in turn promotes further activation of Panx1. In a previous study, we reported that the C-terminus of Panx1 (Panx1-CT) attenuates P2X7R-mediated Ca2+ influx and cell death. One of the distinctive features of P2X7R is the gradual increase in current with repetitive stimulation. In the current study, we report an effect of Panx1-CT (amino acid residues 350 to 426) on P2X7R current, which differs from the effect of full-length Panx1. Panx1-CT inhibited P2X7R current, which persisted in all consecutive agonist applications. However, full-length Panx1 reduced P2X7R current at initial stimulations, followed by gradual augmentation. When P2X7R was activated for an extended period, cells expressing Panx1-CT exhibited less mitochondrial depolarization, reactive oxygen species (ROS) generation, Caspase 3 activation and cell death, whereas cells overexpressing full-length Panx1 showed the opposite effect. Taken together, these findings suggest that Panx1 can either attenuate or augment P2X7R-mediated cellular processes depending on the degree of P2X7R activation.
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Affiliation(s)
- Rutambhara Purohit
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, 600 036, Tamil Nadu, India.
| | - Amal Kanti Bera
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, 600 036, Tamil Nadu, India.
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The Impact of Plasma Membrane Ion Channels on Bone Remodeling in Response to Mechanical Stress, Oxidative Imbalance, and Acidosis. Antioxidants (Basel) 2023; 12:antiox12030689. [PMID: 36978936 PMCID: PMC10045377 DOI: 10.3390/antiox12030689] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/01/2023] [Accepted: 03/03/2023] [Indexed: 03/14/2023] Open
Abstract
The extracellular milieu is a rich source of different stimuli and stressors. Some of them depend on the chemical–physical features of the matrix, while others may come from the ‘outer’ environment, as in the case of mechanical loading applied on the bones. In addition to these forces, a plethora of chemical signals drives cell physiology and fate, possibly leading to dysfunctions when the homeostasis is disrupted. This variety of stimuli triggers different responses among the tissues: bones represent a particular milieu in which a fragile balance between mechanical and metabolic demands should be tuned and maintained by the concerted activity of cell biomolecules located at the interface between external and internal environments. Plasma membrane ion channels can be viewed as multifunctional protein machines that act as rapid and selective dual-nature hubs, sensors, and transducers. Here we focus on some multisensory ion channels (belonging to Piezo, TRP, ASIC/EnaC, P2XR, Connexin, and Pannexin families) actually or potentially playing a significant role in bone adaptation to three main stressors, mechanical forces, oxidative stress, and acidosis, through their effects on bone cells including mesenchymal stem cells, osteoblasts, osteoclasts, and osteocytes. Ion channel-mediated bone remodeling occurs in physiological processes, aging, and human diseases such as osteoporosis, cancer, and traumatic events.
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Caruso G, Di Pietro L, Caraci F. Gap Junctions and Connexins in Microglia-Related Oxidative Stress and Neuroinflammation: Perspectives for Drug Discovery. Biomolecules 2023; 13:biom13030505. [PMID: 36979440 PMCID: PMC10046203 DOI: 10.3390/biom13030505] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/28/2023] [Accepted: 03/07/2023] [Indexed: 03/12/2023] Open
Abstract
Microglia represent the immune system of the brain. Their role is central in two phenomena, neuroinflammation and oxidative stress, which are at the roots of different pathologies related to the central nervous system (CNS). In order to maintain the homeostasis of the brain and re-establish the equilibrium after a threatening imbalance, microglia communicate with each other and other cells within the CNS by receiving specific signals through membrane-bound receptors and then releasing neurotrophic factors into either the extracellular milieu or directly into the cytoplasm of nearby cells, such as astrocytes and neurons. These last two mechanisms rely on the activity of protein structures that enable the formation of channels in the membrane, namely, connexins and pannexins, that group and form gap junctions, hemichannels, and pannexons. These channels allow the release of gliotransmitters, such as adenosine triphosphate (ATP) and glutamate, together with calcium ion (Ca2+), that seem to play a pivotal role in inter-cellular communication. The aim of the present review is focused on the physiology of channel protein complexes and their contribution to neuroinflammatory and oxidative stress-related phenomena, which play a central role in neurodegenerative disorders. We will then discuss how pharmacological modulation of these channels can impact neuroinflammatory phenomena and hypothesize that currently available nutraceuticals, such as carnosine and N-acetylcysteine, can modulate the activity of connexins and pannexins in microglial cells and reduce oxidative stress in neurodegenerative disorders.
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Affiliation(s)
- Giuseppe Caruso
- Department of Drug and Health Sciences, University of Catania, 95123 Catania, Italy
- Unit of Neuropharmacology and Translational Neurosciences, Oasi Research Institute-IRCCS, 94018 Troina, Italy
- Correspondence: ; Tel.: +39-0957385036
| | - Lucia Di Pietro
- Department of Drug and Health Sciences, University of Catania, 95123 Catania, Italy
- Scuola Superiore di Catania, University of Catania, 95123 Catania, Italy
| | - Filippo Caraci
- Department of Drug and Health Sciences, University of Catania, 95123 Catania, Italy
- Unit of Neuropharmacology and Translational Neurosciences, Oasi Research Institute-IRCCS, 94018 Troina, Italy
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7
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Gu L, Sun M, Li R, Tao Y, Luo X, Zhang X, Yuan Y, Xie Z. Microglial pyroptosis: Therapeutic target in secondary brain injury following intracerebral hemorrhage. Front Cell Neurosci 2022; 16:971469. [PMID: 36159393 PMCID: PMC9507402 DOI: 10.3389/fncel.2022.971469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 08/25/2022] [Indexed: 11/25/2022] Open
Abstract
Intracerebral hemorrhage (ICH) is a major cerebrovascular illness that causes substantial neurological sequelae and dysfunction caused by secondary brain injury (SBI), and there are no effective therapies to mitigate the disability. Microglia, the brain-resident macrophage, participates in the primary inflammatory response, and activation of microglia to an M1-like phenotype largely takes place in the acute phase following ICH. A growing body of research suggests that the pathophysiology of SBI after ICH is mediated by an inflammatory response mediated by microglial-pyroptotic inflammasomes, while inhibiting the activation of microglial pyroptosis could suppress the inflammatory cascade reaction, thus attenuating the brain injury after ICH. Pyroptosis is characterized by rapid plasma membrane disruption, followed by the release of cellular contents and pro-inflammatory mediators. In this review, we outline the molecular mechanism of microglial pyroptosis and summarize the up-to-date evidence of its involvement in the pathological process of ICH, and highlight microglial pyroptosis-targeted strategies that have the potential to cure intracerebral hemorrhage. This review contributes to a better understanding of the function of microglial pyroptosis in ICH and assesses it as a possible therapeutic target.
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8
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Purohit R, Bera AK. Pannexin 1 plays a pro-survival role by attenuating P2X7 receptor-mediated Ca 2+ influx. Cell Calcium 2021; 99:102458. [PMID: 34479067 DOI: 10.1016/j.ceca.2021.102458] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 07/27/2021] [Accepted: 08/16/2021] [Indexed: 10/20/2022]
Abstract
Extracellular ATP works as an autocrine and/or paracrine signaling molecule by activating plasma membrane-localized purinergic receptors. Stimulation of purinergic P2X7 receptor (P2X7R) increases cytosolic Ca2+ ([Ca2+]c), which in turn activates Pannexin 1 (Panx1) channel. In earlier studies, Panx1 and P2X7R have been shown to interact physically. Also, both the channels have been implicated in similar pathophysiological processes. In this study, we investigated the effect of Panx1 on P2X7R-mediated Ca2+influx. Panx1 attenuated P2X7R-mediated [Ca2+]c rise in CHO-K1 and HEK-293 cells. [Ca2+]c rise was higher in Panx1 knockdown astrocytes. The inhibitory effect was unaffected in the presence of Panx1 blocker, carbenoxolone. The region between 350th and 386th amino acid residues in the carboxyl terminus (CT) of Panx1 was found to be crucial for inhibiting P2X7R. Like full-length Panx1, the CT (350th to 426th amino acids) alone was able to attenuate the [Ca2+]c rise. Further, CT prevented cell death caused by P2X7R overactivation. Based on our results, we propose a novel pro-survival role of Panx1 exerted by modulating P2X7R.
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Affiliation(s)
- Rutambhara Purohit
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600 036, India
| | - Amal Kanti Bera
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600 036, India.
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9
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Prieto-Villalobos J, Alvear TF, Liberona A, Lucero CM, Martínez-Araya CJ, Balmazabal J, Inostroza CA, Ramírez G, Gómez GI, Orellana JA. Astroglial Hemichannels and Pannexons: The Hidden Link between Maternal Inflammation and Neurological Disorders. Int J Mol Sci 2021; 22:ijms22179503. [PMID: 34502412 PMCID: PMC8430734 DOI: 10.3390/ijms22179503] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 08/30/2021] [Accepted: 08/30/2021] [Indexed: 12/11/2022] Open
Abstract
Maternal inflammation during pregnancy causes later-in-life alterations of the offspring’s brain structure and function. These abnormalities increase the risk of developing several psychiatric and neurological disorders, including schizophrenia, intellectual disability, bipolar disorder, autism spectrum disorder, microcephaly, and cerebral palsy. Here, we discuss how astrocytes might contribute to postnatal brain dysfunction following maternal inflammation, focusing on the signaling mediated by two families of plasma membrane channels: hemi-channels and pannexons. [Ca2+]i imbalance linked to the opening of astrocytic hemichannels and pannexons could disturb essential functions that sustain astrocytic survival and astrocyte-to-neuron support, including energy and redox homeostasis, uptake of K+ and glutamate, and the delivery of neurotrophic factors and energy-rich metabolites. Both phenomena could make neurons more susceptible to the harmful effect of prenatal inflammation and the experience of a second immune challenge during adulthood. On the other hand, maternal inflammation could cause excitotoxicity by producing the release of high amounts of gliotransmitters via astrocytic hemichannels/pannexons, eliciting further neuronal damage. Understanding how hemichannels and pannexons participate in maternal inflammation-induced brain abnormalities could be critical for developing pharmacological therapies against neurological disorders observed in the offspring.
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Affiliation(s)
- Juan Prieto-Villalobos
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.P.-V.); (T.F.A.); (A.L.); (C.J.M.-A.); (J.B.); (C.A.I.); (G.R.)
| | - Tanhia F. Alvear
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.P.-V.); (T.F.A.); (A.L.); (C.J.M.-A.); (J.B.); (C.A.I.); (G.R.)
| | - Andrés Liberona
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.P.-V.); (T.F.A.); (A.L.); (C.J.M.-A.); (J.B.); (C.A.I.); (G.R.)
| | - Claudia M. Lucero
- Institute of Biomedical Sciences, Faculty of Health Sciences, Universidad Autónoma de Chile, Santiago 8910060, Chile; (C.M.L.); (G.I.G.)
| | - Claudio J. Martínez-Araya
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.P.-V.); (T.F.A.); (A.L.); (C.J.M.-A.); (J.B.); (C.A.I.); (G.R.)
| | - Javiera Balmazabal
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.P.-V.); (T.F.A.); (A.L.); (C.J.M.-A.); (J.B.); (C.A.I.); (G.R.)
| | - Carla A. Inostroza
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.P.-V.); (T.F.A.); (A.L.); (C.J.M.-A.); (J.B.); (C.A.I.); (G.R.)
| | - Gigliola Ramírez
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.P.-V.); (T.F.A.); (A.L.); (C.J.M.-A.); (J.B.); (C.A.I.); (G.R.)
| | - Gonzalo I. Gómez
- Institute of Biomedical Sciences, Faculty of Health Sciences, Universidad Autónoma de Chile, Santiago 8910060, Chile; (C.M.L.); (G.I.G.)
| | - Juan A. Orellana
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.P.-V.); (T.F.A.); (A.L.); (C.J.M.-A.); (J.B.); (C.A.I.); (G.R.)
- Correspondence: ; Tel.: +56-23548105
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Zhu CS, Wang W, Qiang X, Chen W, Lan X, Li J, Wang H. Endogenous Regulation and Pharmacological Modulation of Sepsis-Induced HMGB1 Release and Action: An Updated Review. Cells 2021; 10:2220. [PMID: 34571869 PMCID: PMC8469563 DOI: 10.3390/cells10092220] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 08/13/2021] [Accepted: 08/24/2021] [Indexed: 12/12/2022] Open
Abstract
Sepsis remains a common cause of death in intensive care units, accounting for approximately 20% of total deaths worldwide. Its pathogenesis is partly attributable to dysregulated inflammatory responses to bacterial endotoxins (such as lipopolysaccharide, LPS), which stimulate innate immune cells to sequentially release early cytokines (such as tumor necrosis factor (TNF) and interferons (IFNs)) and late mediators (such as high-mobility group box 1, HMGB1). Despite difficulties in translating mechanistic insights into effective therapies, an improved understanding of the complex mechanisms underlying the pathogenesis of sepsis is still urgently needed. Here, we review recent progress in elucidating the intricate mechanisms underlying the regulation of HMGB1 release and action, and propose a few potential therapeutic candidates for future clinical investigations.
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Affiliation(s)
- Cassie Shu Zhu
- The Feinstein Institutes for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY 11030, USA; (C.S.Z.); (X.Q.); (W.C.); (X.L.); (J.L.)
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, 500 Hofstra Blvd, Hempstead, NY 11549, USA
| | - Wei Wang
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA 24061, USA;
| | - Xiaoling Qiang
- The Feinstein Institutes for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY 11030, USA; (C.S.Z.); (X.Q.); (W.C.); (X.L.); (J.L.)
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, 500 Hofstra Blvd, Hempstead, NY 11549, USA
| | - Weiqiang Chen
- The Feinstein Institutes for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY 11030, USA; (C.S.Z.); (X.Q.); (W.C.); (X.L.); (J.L.)
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, 500 Hofstra Blvd, Hempstead, NY 11549, USA
| | - Xiqian Lan
- The Feinstein Institutes for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY 11030, USA; (C.S.Z.); (X.Q.); (W.C.); (X.L.); (J.L.)
| | - Jianhua Li
- The Feinstein Institutes for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY 11030, USA; (C.S.Z.); (X.Q.); (W.C.); (X.L.); (J.L.)
| | - Haichao Wang
- The Feinstein Institutes for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY 11030, USA; (C.S.Z.); (X.Q.); (W.C.); (X.L.); (J.L.)
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, 500 Hofstra Blvd, Hempstead, NY 11549, USA
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11
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Giaume C, Naus CC, Sáez JC, Leybaert L. Glial Connexins and Pannexins in the Healthy and Diseased Brain. Physiol Rev 2020; 101:93-145. [PMID: 32326824 DOI: 10.1152/physrev.00043.2018] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Over the past several decades a large amount of data have established that glial cells, the main cell population in the brain, dynamically interact with neurons and thus impact their activity and survival. One typical feature of glia is their marked expression of several connexins, the membrane proteins forming intercellular gap junction channels and hemichannels. Pannexins, which have a tetraspan membrane topology as connexins, are also detected in glial cells. Here, we review the evidence that connexin and pannexin channels are actively involved in dynamic and metabolic neuroglial interactions in physiological as well as in pathological situations. These features of neuroglial interactions open the way to identify novel non-neuronal aspects that allow for a better understanding of behavior and information processing performed by neurons. This will also complement the "neurocentric" view by facilitating the development of glia-targeted therapeutic strategies in brain disease.
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Affiliation(s)
- Christian Giaume
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050, Paris, France; University Pierre et Marie Curie, Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, Paris, France; Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile; Instituo de Neurociencias, Centro Interdisciplinario de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile; Physiology Group, Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Christian C Naus
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050, Paris, France; University Pierre et Marie Curie, Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, Paris, France; Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile; Instituo de Neurociencias, Centro Interdisciplinario de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile; Physiology Group, Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Juan C Sáez
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050, Paris, France; University Pierre et Marie Curie, Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, Paris, France; Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile; Instituo de Neurociencias, Centro Interdisciplinario de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile; Physiology Group, Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Luc Leybaert
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050, Paris, France; University Pierre et Marie Curie, Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, Paris, France; Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile; Instituo de Neurociencias, Centro Interdisciplinario de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile; Physiology Group, Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
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12
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Tachikawa M, Akaogi R, Taii A, Akanuma SI, Uchida Y, Terasaki T. Distinct Transport Properties of Human Pannexin 1 and Connexin 32 Hemichannels. J Pharm Sci 2020; 109:1395-1402. [PMID: 31837976 DOI: 10.1016/j.xphs.2019.12.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 12/05/2019] [Accepted: 12/06/2019] [Indexed: 11/19/2022]
Abstract
Pannexin (Px) and connexin (Cx) hemichannels mediate bidirectional membrane transport in response to various stimuli and are involved in drug efficacy and toxicity. The purpose of the present study was to clarify in detail the transport characteristics of Px1 and Cx32 hemichannels by establishing transport assay systems using human Px1- and P2RX7 receptor-overexpressing HEK293 cells (Px1/P2RX7/HEK293) and Cx32-overexpressing HEK293 cells (Cx32/HEK293), in which P2RX7 and an extracellular Ca2+-depleted condition serve as the opening trigger, respectively. Uptake of the cationic fluorescent dye propidium iodide (PI) was significantly increased in Px1/P2RX7/HEK293 cells compared to that in mock cells, whereas there was no significant uptake of the anionic fluorescent dye sulforhodamine 101 (SR101). Uptake of [3H]cholesterol by Px1/P2RX7/HEK293 cells was significantly decreased, whereas that of [3H]taurine was not, compared to mock cells. On the other hand, uptakes of PI and SR-101 by Cx32/HEK293 cells were both significantly increased compared to mock cells. The PI uptake by Cx32/HEK293 cells was significantly inhibited by thioacetamide, acetaminophen, and N-acetyl-p-benzoquinoneimine. Cellular uptake of [3H]cholesterol was significantly increased in Cx32/HEK293 cells and that of [3H]taurine was significantly decreased. These results support the idea that Px1 and Cx32 hemichannels have distinct substrate recognition specificities and transport directions.
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Affiliation(s)
- Masanori Tachikawa
- Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aramaki, Aoba, Sendai 980-8578, Japan; Graduate School of Biomedical Sciences, Tokushima University, 1-78-1 Shomachi, Tokushima 770-8505, Japan.
| | - Ryo Akaogi
- Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aramaki, Aoba, Sendai 980-8578, Japan
| | - Ayaka Taii
- Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aramaki, Aoba, Sendai 980-8578, Japan
| | - Shin-Ichi Akanuma
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Yasuo Uchida
- Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aramaki, Aoba, Sendai 980-8578, Japan
| | - Tetsuya Terasaki
- Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aramaki, Aoba, Sendai 980-8578, Japan
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13
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Tachikawa M, Murakami K, Akaogi R, Akanuma SI, Terasaki T, Hosoya KI. Polarized hemichannel opening of pannexin 1/connexin 43 contributes to dysregulation of transport function in blood-brain barrier endothelial cells. Neurochem Int 2019; 132:104600. [PMID: 31712070 DOI: 10.1016/j.neuint.2019.104600] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Revised: 10/18/2019] [Accepted: 11/07/2019] [Indexed: 01/06/2023]
Abstract
Dysregulation of blood-brain barrier (BBB) transport exacerbates brain damage in acute ischemic stroke. Here, we aimed to investigate the mechanism of this BBB transport dysregulation by studying the localization and function of pannexin (Px) and connexin (Cx) hemichannels in blood-brain barrier endothelial cells of rat (TR-BBB13 cells) and human (hCMEC/D3 cells) under acute ischemic stroke-mimicking oxygen/glucose deprivation (OGD) and extracellular Ca2+ ([Ca2+]e)-free conditions. TR-BBB13 cells showed increased uptake of hemichannel-permeable sulforhodamine 101, and this increase was markedly inhibited by carbenoxolone, a hemichannel inhibitor. Transcripts of Px1 and Cx43 were detected in TR-BBB13 cells and freshly isolated brain microvascular endothelial cells. The basal compartment-to-cell uptake of hemichannel-permeable propidium iodide was selectively enhanced in hCMEC/D3 cells under [Ca2+]e-free conditions in the basal Transwell chamber. Immunohistochemical analysis revealed the predominant localization of Cx43 on the lateral membranes of hCMEC/D3 cells. [3H]Taurine uptake by hCMEC/D3 cells was significantly reduced in the absence of [Ca2+]e. Functional knock-down of Px1 and Cx43 with mimetic peptides significantly inhibited the increase of ATP release from hCMEC/D3 cells under [Ca2+]e-free conditions. These results suggest that polarized Px1/Cx43 hemichannel opening in brain capillary endothelial cells under acute ischemic stroke-mimicking conditions contributes to dysregulation of BBB transport function, resulting in release of intracellular taurine and ATP.
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Affiliation(s)
- Masanori Tachikawa
- Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan; Graduate School of Biomedical Sciences, Tokushima University, Tokushima, Japan.
| | - Koji Murakami
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Ryo Akaogi
- Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Shin-Ichi Akanuma
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Tetsuya Terasaki
- Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Ken-Ichi Hosoya
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
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14
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Chávez CE, Oyarzún JE, Avendaño BC, Mellado LA, Inostroza CA, Alvear TF, Orellana JA. The Opening of Connexin 43 Hemichannels Alters Hippocampal Astrocyte Function and Neuronal Survival in Prenatally LPS-Exposed Adult Offspring. Front Cell Neurosci 2019; 13:460. [PMID: 31680871 PMCID: PMC6797550 DOI: 10.3389/fncel.2019.00460] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 09/27/2019] [Indexed: 01/19/2023] Open
Abstract
Clinical evidence has revealed that children born from mothers exposed to viral and bacterial pathogens during pregnancy are more likely to suffer various neurological disorders including schizophrenia, autism bipolar disorder, major depression, epilepsy, and cerebral palsy. Despite that most research has centered on the impact of prenatal inflammation in neurons and microglia, the potential modifications of astrocytes and neuron-astrocyte communication have received less scrutiny. Here, we evaluated whether prenatally LPS-exposed offspring display alterations in the opening of astrocyte hemichannels and pannexons in the hippocampus, together with changes in neuroinflammation, intracellular Ca2+ and nitric oxide (NO) signaling, gliotransmitter release, cell arborization, and neuronal survival. Ethidium uptake recordings revealed that prenatal LPS exposure enhances the opening of astrocyte Cx43 hemichannels and Panx1 channels in the hippocampus of adult offspring mice. This enhanced channel activity occurred by a mechanism involving a microglia-dependent production of IL-1β/TNF-α and the stimulation of p38 MAP kinase/iNOS/[Ca2+]i-mediated signaling and purinergic/glutamatergic pathways. Noteworthy, the activity of Cx43 hemichannels affected the release of glutamate, [Ca2+]i handling, and morphology of astrocytes, whereas also disturbed neuronal function, including the dendritic arbor and spine density, as well as survival. We speculate that excitotoxic levels of glutamate triggered by the activation of Cx43 hemichannels may contribute to hippocampal neurotoxicity and damage in prenatally LPS-exposed offspring. Therefore, the understanding of how astrocyte-neuron crosstalk is an auspicious avenue toward the development of broad treatments for several neurological disorders observed in children born to women who had a severe infection during gestation.
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Affiliation(s)
- Carolina E Chávez
- Departamento de Neurología, Facultad de Medicina, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan E Oyarzún
- Departamento de Neurología, Facultad de Medicina, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Beatriz C Avendaño
- Departamento de Neurología, Facultad de Medicina, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Luis A Mellado
- Departamento de Neurología, Facultad de Medicina, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Carla A Inostroza
- Departamento de Neurología, Facultad de Medicina, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Tanhia F Alvear
- Departamento de Neurología, Facultad de Medicina, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan A Orellana
- Departamento de Neurología, Facultad de Medicina, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Pontificia Universidad Católica de Chile, Santiago, Chile
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15
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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: 156] [Impact Index Per Article: 31.2] [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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16
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Vejar S, Oyarzún JE, Retamal MA, Ortiz FC, Orellana JA. Connexin and Pannexin-Based Channels in Oligodendrocytes: Implications in Brain Health and Disease. Front Cell Neurosci 2019; 13:3. [PMID: 30760982 PMCID: PMC6361860 DOI: 10.3389/fncel.2019.00003] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 01/07/2019] [Indexed: 11/13/2022] Open
Abstract
Oligodendrocytes are the myelin forming cells in the central nervous system (CNS). In addition to this main physiological function, these cells play key roles by providing energy substrates to neurons as well as information required to sustain proper synaptic transmission and plasticity at the CNS. The latter requires a fine coordinated intercellular communication with neurons and other glial cell types, including astrocytes. In mammals, tissue synchronization is mainly mediated by connexins and pannexins, two protein families that underpin the communication among neighboring cells through the formation of different plasma membrane channels. At one end, gap junction channels (GJCs; which are exclusively formed by connexins in vertebrates) connect the cytoplasm of contacting cells allowing electrical and metabolic coupling. At the other end, hemichannels and pannexons (which are formed by connexins and pannexins, respectively) communicate the intra- and extracellular compartments, serving as diffusion pathways of ions and small molecules. Here, we briefly review the current knowledge about the expression and function of hemichannels, pannexons and GJCs in oligodendrocytes, as well as the evidence regarding the possible role of these channels in metabolic and synaptic functions at the CNS. In particular, we focus on oligodendrocyte-astrocyte coupling during axon metabolic support and its implications in brain health and disease.
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Affiliation(s)
- Sebastián Vejar
- Mechanisms of Myelin Formation and Repair Laboratory, Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile
| | - Juan E. Oyarzún
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Investigación y Estudio del Consumo de Alcohol en Adolescentes, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Mauricio A. Retamal
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo, Santiago, Chile
- Department of Cell Physiology and Molecular Biophysics, and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - Fernando C. Ortiz
- Mechanisms of Myelin Formation and Repair Laboratory, Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile
| | - Juan A. Orellana
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Investigación y Estudio del Consumo de Alcohol en Adolescentes, Pontificia Universidad Católica de Chile, Santiago, Chile
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17
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Baba M, Endoh M, Ma W, Toyama H, Hirayama A, Nishikawa K, Takubo K, Hano H, Hasumi H, Umemoto T, Hashimoto M, Irie N, Esumi C, Kataoka M, Nakagata N, Soga T, Yao M, Kamba T, Minami T, Ishii M, Suda T. Folliculin Regulates Osteoclastogenesis Through Metabolic Regulation. J Bone Miner Res 2018; 33:1785-1798. [PMID: 29893999 PMCID: PMC6220829 DOI: 10.1002/jbmr.3477] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Revised: 05/08/2018] [Accepted: 05/23/2018] [Indexed: 12/19/2022]
Abstract
Osteoclast differentiation is a dynamic differentiation process, which is accompanied by dramatic changes in metabolic status as well as in gene expression. Recent findings have revealed an essential connection between metabolic reprogramming and dynamic gene expression changes during osteoclast differentiation. However, the upstream regulatory mechanisms that drive these metabolic changes in osteoclastogenesis remain to be elucidated. Here, we demonstrate that induced deletion of a tumor suppressor gene, Folliculin (Flcn), in mouse osteoclast precursors causes severe osteoporosis in 3 weeks through excess osteoclastogenesis. Flcn-deficient osteoclast precursors reveal cell autonomous accelerated osteoclastogenesis with increased sensitivity to receptor activator of NF-κB ligand (RANKL). We demonstrate that Flcn regulates oxidative phosphorylation and purine metabolism through suppression of nuclear localization of the transcription factor Tfe3, thereby inhibiting expression of its target gene Pgc1. Metabolome studies revealed that Flcn-deficient osteoclast precursors exhibit significant augmentation of oxidative phosphorylation and nucleotide production, resulting in an enhanced purinergic signaling loop that is composed of controlled ATP release and autocrine/paracrine purinergic receptor stimulation. Inhibition of this purinergic signaling loop efficiently blocks accelerated osteoclastogenesis in Flcn-deficient osteoclast precursors. Here, we demonstrate an essential and novel role of the Flcn-Tfe3-Pgc1 axis in osteoclastogenesis through the metabolic reprogramming of oxidative phosphorylation and purine metabolism. © 2018 The Authors Journal of Bone and Mineral Research published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Masaya Baba
- International Research Center for Medical Sciences (IRCMS)Kumamoto UniversityKumamotoJapan
| | - Mitsuhiro Endoh
- International Research Center for Medical Sciences (IRCMS)Kumamoto UniversityKumamotoJapan
- Cancer Science Institute of SingaporeNational University of SingaporeCentre for Translational MedicineSingapore
| | - Wenjuan Ma
- International Research Center for Medical Sciences (IRCMS)Kumamoto UniversityKumamotoJapan
| | - Hirofumi Toyama
- Department of Cell DifferentiationThe Sakaguchi Laboratory of Developmental BiologySchool of MedicineKeio UniversityTokyoJapan
| | | | - Keizo Nishikawa
- Immunology Frontier Research CenterOsaka UniversityOsakaJapan
| | - Keiyo Takubo
- Department of Cell DifferentiationThe Sakaguchi Laboratory of Developmental BiologySchool of MedicineKeio UniversityTokyoJapan
- Department of Stem Cell BiologyResearch InstituteNational Center for Global Health and MedicineTokyoJapan
| | - Hiroyuki Hano
- International Research Center for Medical Sciences (IRCMS)Kumamoto UniversityKumamotoJapan
| | - Hisashi Hasumi
- Department of UrologyYokohama City University Graduate School of MedicineYokohamaJapan
| | - Terumasa Umemoto
- International Research Center for Medical Sciences (IRCMS)Kumamoto UniversityKumamotoJapan
| | - Michihiro Hashimoto
- International Research Center for Medical Sciences (IRCMS)Kumamoto UniversityKumamotoJapan
| | - Nobuko Irie
- International Research Center for Medical Sciences (IRCMS)Kumamoto UniversityKumamotoJapan
| | - Chiharu Esumi
- International Research Center for Medical Sciences (IRCMS)Kumamoto UniversityKumamotoJapan
| | - Miho Kataoka
- International Research Center for Medical Sciences (IRCMS)Kumamoto UniversityKumamotoJapan
| | - Naomi Nakagata
- Division of Reproductive EngineeringCenter for Animal Resources and Development (CARD)Kumamoto UniversityKumamotoJapan
| | - Tomoyoshi Soga
- Institute for Advanced BiosciencesKeio UniversityYamagataJapan
| | - Masahiro Yao
- Department of UrologyYokohama City University Graduate School of MedicineYokohamaJapan
| | - Tomomi Kamba
- Department of UrologyFaculty of Life SciencesKumamoto UniversityKumamotoJapan
| | - Takashi Minami
- Division of Molecular and Vascular BiologyInstitute of Resource Development and Analysis (IRDA)Kumamoto UniversityKumamotoJapan
| | - Masaru Ishii
- Department of Immunology and Cell BiologyGraduate School of Medicine and Frontier BiosciencesOsaka UniversityOsakaJapan
| | - Toshio Suda
- International Research Center for Medical Sciences (IRCMS)Kumamoto UniversityKumamotoJapan
- Cancer Science Institute of SingaporeNational University of SingaporeCentre for Translational MedicineSingapore
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18
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Osipova ED, Semyachkina-Glushkovskaya OV, Morgun AV, Pisareva NV, Malinovskaya NA, Boitsova EB, Pozhilenkova EA, Belova OA, Salmin VV, Taranushenko TE, Noda M, Salmina AB. Gliotransmitters and cytokines in the control of blood-brain barrier permeability. Rev Neurosci 2018; 29:567-591. [DOI: 10.1515/revneuro-2017-0092] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 11/26/2017] [Indexed: 11/15/2022]
Abstract
AbstractThe contribution of astrocytes and microglia to the regulation of neuroplasticity or neurovascular unit (NVU) is based on the coordinated secretion of gliotransmitters and cytokines and the release and uptake of metabolites. Blood-brain barrier (BBB) integrity and angiogenesis are influenced by perivascular cells contacting with the abluminal side of brain microvessel endothelial cells (pericytes, astrocytes) or by immune cells existing (microglia) or invading the NVU (macrophages) under pathologic conditions. The release of gliotransmitters or cytokines by activated astroglial and microglial cells is provided by distinct mechanisms, affects intercellular communication, and results in the establishment of microenvironment controlling BBB permeability and neuroinflammation. Glial glutamate transporters and connexin and pannexin hemichannels working in the tight functional coupling with the purinergic system serve as promising molecular targets for manipulating the intercellular communications that control BBB permeability in brain pathologies associated with excessive angiogenesis, cerebrovascular remodeling, and BBB-mediated neuroinflammation. Substantial progress in deciphering the molecular mechanisms underlying the (patho)physiology of perivascular glia provides promising approaches to novel clinically relevant therapies for brain disorders. The present review summarizes the current understandings on the secretory machinery expressed in glial cells (glutamate transporters, connexin and pannexin hemichannels, exocytosis mechanisms, membrane-derived microvesicles, and inflammasomes) and the role of secreted gliotransmitters and cytokines in the regulation of NVU and BBB permeability in (patho)physiologic conditions.
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19
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Expression and function of connexin 43 protein in mouse and human retinal pigment epithelial cells as hemichannels and gap junction proteins. Exp Eye Res 2018; 168:128-137. [DOI: 10.1016/j.exer.2018.01.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 01/18/2018] [Accepted: 01/18/2018] [Indexed: 01/08/2023]
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20
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Li S, Bjelobaba I, Stojilkovic SS. Interactions of Pannexin1 channels with purinergic and NMDA receptor channels. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2018; 1860:166-173. [PMID: 28389204 PMCID: PMC5628093 DOI: 10.1016/j.bbamem.2017.03.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 03/28/2017] [Accepted: 03/29/2017] [Indexed: 12/31/2022]
Abstract
Pannexins are a three-member family of vertebrate plasma membrane spanning molecules that have homology to the invertebrate gap junction forming proteins, the innexins. However, pannexins do not form gap junctions but operate as plasma membrane channels. The best-characterized member of these proteins, Pannexin1 (Panx1) was suggested to be functionally associated with purinergic P2X and N-methyl-D-aspartate (NMDA) receptor channels. Activation of these receptor channels by their endogenous ligands leads to cross-activation of Panx1 channels. This in turn potentiates P2X and NMDA receptor channel signaling. Two potentiation concepts have been suggested: enhancement of the current responses and/or sustained receptor channel activation by ATP released through Panx1 pore and adenosine generated by ectonucleotidase-dependent dephosphorylation of ATP. Here we summarize the current knowledge and hypotheses about interactions of Panx1 channels with P2X and NMDA receptor channels. This article is part of a Special Issue entitled: Gap Junction Proteins edited by Jean Claude Herve.
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Affiliation(s)
- Shuo Li
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, Tianjin 300387, China
| | - Ivana Bjelobaba
- Institute for Biological Research "Sinisa Stankovic", University of Belgrade, 11000 Belgrade, Serbia
| | - Stanko S Stojilkovic
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA.
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21
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Dong L, Cheng X, Zhou L, Hu Y. Calcium channels are involved in EphB/ephrinB reverse signaling‑induced apoptosis in a rat chronic ocular hypertension model. Mol Med Rep 2017; 17:2465-2471. [PMID: 29207174 PMCID: PMC5783492 DOI: 10.3892/mmr.2017.8162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Accepted: 11/21/2017] [Indexed: 11/25/2022] Open
Abstract
Erythropoietin-producing hepatocyte receptor B (EphB)/ephrinB reverse signaling has been revealed to be activated in chronic ocular hypertension (COH) by increasing the apoptosis of retinal ganglion cells (RGCs). However, the exact mechanism is not well understood. The present study investigated the involvement of Ca2+ channels in the apoptosis of RGCs induced by EphB/ephrinB reverse signaling in a rat CHO model, which was established by cauterizing 3 out of the 4 episcleral veins. The expression levels of four voltage-gated Ca2+ channel subunits (Cav3.1–3.3 and Cav1.2) were detected using immunofluorescence and western blot analysis. TUNEL staining was performed to assess RGC apoptosis following an injection with the T type Ca2+ channel blocker. Ca2+ channels, mainly the T type, were upregulated in COH rat retinas when compared with the sham group (P<0.01). Additionally, the Cav3.2 subunit of T type calcium channels was predominantly expressed in Müller cells and RGCs, such as ephrinB2. Furthermore, an intravitreal injection of the Ca2+ channel blocker Mibefradil (3 µM) reduced EphB2-fragment crystallizable region-induced RGC apoptosis in normal rats. Thus, the results suggest that Ca2+ channels in a COH model may be a pathway involved in ephrinB/EphB signaling-induced RGC apoptosis.
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Affiliation(s)
- Lingdan Dong
- Central Laboratory, First People's Hospital of Jingzhou, First Affiliated Hospital of Yangtze University, Jingzhou, Hubei 434000, P.R. China
| | - Xianglin Cheng
- Department of Neurology, First People's Hospital of Jingzhou, First Affiliated Hospital of Yangtze University, Jingzhou, Hubei 434000, P.R. China
| | - Long Zhou
- Department of Pathology, First People's Hospital of Jingzhou, First Affiliated Hospital of Yangtze University, Jingzhou, Hubei 434000, P.R. China
| | - Yanhong Hu
- Nursing Department of Medical School of Yangtze University, Jingzhou, Hubei 434000, P.R. China
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22
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Beltrán-Castillo S, Olivares MJ, Contreras RA, Zúñiga G, Llona I, von Bernhardi R, Eugenín JL. D-serine released by astrocytes in brainstem regulates breathing response to CO 2 levels. Nat Commun 2017; 8:838. [PMID: 29018191 PMCID: PMC5635109 DOI: 10.1038/s41467-017-00960-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 08/09/2017] [Indexed: 11/17/2022] Open
Abstract
Central chemoreception is essential for adjusting breathing to physiological demands, and for maintaining CO2 and pH homeostasis in the brain. CO2-induced ATP release from brainstem astrocytes stimulates breathing. NMDA receptor (NMDAR) antagonism reduces the CO2-induced hyperventilation by unknown mechanisms. Here we show that astrocytes in the mouse caudal medullary brainstem can synthesize, store, and release d-serine, an agonist for the glycine-binding site of the NMDAR, in response to elevated CO2 levels. We show that systemic and raphe nucleus d-serine administration to awake, unrestrained mice increases the respiratory frequency. Application of d-serine to brainstem slices also increases respiratory frequency, which was prevented by NMDAR blockade. Inhibition of d-serine synthesis, enzymatic degradation of d-serine, or the sodium fluoroacetate-induced impairment of astrocyte functions decrease the basal respiratory frequency and the CO2-induced respiratory response in vivo and in vitro. Our findings suggest that astrocytic release of d-serine may account for the glutamatergic contribution to central chemoreception. Astrocytes are involved in chemoreception in brainstem areas that regulate breathing rhythm, and astrocytes are known to release d-serine. Here the authors show that astrocyte release of d-serine contributes to CO2 sensing and breathing in brainstem slices, and in vivo in awake unrestrained mice.
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Affiliation(s)
- S Beltrán-Castillo
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, USACH, Santiago, 9170022, Chile
| | - M J Olivares
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, USACH, Santiago, 9170022, Chile
| | - R A Contreras
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, USACH, Santiago, 9170022, Chile
| | - G Zúñiga
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, USACH, Santiago, 9170022, Chile
| | - I Llona
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, USACH, Santiago, 9170022, Chile
| | - R von Bernhardi
- Departamento de Neurología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, 8330024, Chile.
| | - J L Eugenín
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, USACH, Santiago, 9170022, Chile.
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23
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Karasawa A, Michalski K, Mikhelzon P, Kawate T. The P2X7 receptor forms a dye-permeable pore independent of its intracellular domain but dependent on membrane lipid composition. eLife 2017; 6:31186. [PMID: 28920575 PMCID: PMC5624784 DOI: 10.7554/elife.31186] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 09/15/2017] [Indexed: 12/15/2022] Open
Abstract
The P2X7 receptor mediates extracellular ATP signaling implicated in the development of devastating diseases such as chronic pain and cancer. Activation of the P2X7 receptor leads to opening of the characteristic dye-permeable membrane pore for molecules up to ~900 Da. However, it remains controversial what constitutes this peculiar pore and how it opens. Here we show that the panda receptor, when purified and reconstituted into liposomes, forms an intrinsic dye-permeable pore in the absence of other cellular components. Unexpectedly, we found that this pore opens independent of its unique C-terminal domain. We also found that P2X7 channel activity is facilitated by phosphatidylglycerol and sphingomyelin, but dominantly inhibited by cholesterol through direct interactions with the transmembrane domain. In combination with cell-based functional studies, our data suggest that the P2X7 receptor itself constitutes a lipid-composition dependent dye-permeable pore, whose opening is facilitated by palmitoylated cysteines near the pore-lining helix.
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Affiliation(s)
- Akira Karasawa
- Department of Molecular Medicine, Cornell University, Ithaca, United States
| | - Kevin Michalski
- Department of Molecular Medicine, Cornell University, Ithaca, United States
| | - Polina Mikhelzon
- Department of Molecular Medicine, Cornell University, Ithaca, United States
| | - Toshimitsu Kawate
- Department of Molecular Medicine, Cornell University, Ithaca, United States
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24
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Swayne LA, Boyce AKJ. Regulation of Pannexin 1 Surface Expression by Extracellular ATP: Potential Implications for Nervous System Function in Health and Disease. Front Cell Neurosci 2017; 11:230. [PMID: 28848396 PMCID: PMC5550711 DOI: 10.3389/fncel.2017.00230] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 07/24/2017] [Indexed: 02/02/2023] Open
Abstract
Pannexin 1 (Panx1) channels are widely recognized for their role in ATP release, and as follows, their function is closely tied to that of ATP-activated P2X7 purinergic receptors (P2X7Rs). Our recent work has shown that extracellular ATP induces clustering of Panx1 with P2X7Rs and their subsequent internalization through a non-canonical cholesterol-dependent mechanism. In other words, we have demonstrated that extracellular ATP levels can regulate the cell surface expression of Panx1. Here we discuss two situations in which we hypothesize that ATP modulation of Panx1 surface expression could be relevant for central nervous system function. The first scenario involves the development of new neurons in the ventricular zone. We propose that ATP-induced Panx1 endocytosis could play an important role in regulating the balance of cell proliferation, survival, and differentiation within this neurogenic niche in the healthy brain. The second scenario relates to the spinal cord, in which we posit that an impairment of ATP-induced Panx1 endocytosis could contribute to pathological neuroplasticity. Together, the discussion of these hypotheses serves to highlight important outstanding questions regarding the interplay between extracellular ATP, Panx1, and P2X7Rs in the nervous system in health and disease.
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Affiliation(s)
- Leigh A Swayne
- Division of Medical Sciences and Island Medical Program, University of Victoria, VictoriaBC, Canada.,Department of Cellular and Physiological Sciences, University of British Columbia, VancouverBC, Canada
| | - Andrew K J Boyce
- Division of Medical Sciences and Island Medical Program, University of Victoria, VictoriaBC, Canada
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25
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Whyte-Fagundes P, Zoidl G. Mechanisms of pannexin1 channel gating and regulation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:65-71. [PMID: 28735901 DOI: 10.1016/j.bbamem.2017.07.009] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 07/17/2017] [Accepted: 07/18/2017] [Indexed: 01/07/2023]
Abstract
Pannexins are a family of integral membrane proteins with distinct post-translational modifications, sub-cellular localization and tissue distribution. Panx1 is the most studied and best-characterized isoform of this gene family. The ubiquitous expression, as well as its function as a major ATP release and nucleotide permeation channel, makes Panx1 a primary candidate for participating in the pathophysiology of CNS disorders. While many investigations revolve around Panx1 functions in health and disease, more recently, details started emerging about mechanisms that control Panx1 channel activity. These advancements in Panx1 biology have revealed that beyond its classical role as an unopposed plasma membrane channel, it participates in alternative pathways involving multiple intracellular compartments, protein complexes and a myriad of extracellular participants. Here, we review recent progress in our understanding of Panx1 at the center of these pathways, highlighting its modulation in a context specific manner. This article is part of a Special Issue entitled: Gap Junction Proteins edited by Jean Claude Herve.
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Affiliation(s)
| | - Georg Zoidl
- Biology, York University, Toronto, Canada; Psychology, York University, Toronto, Canada.
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26
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Chen SP, Qin T, Seidel JL, Zheng Y, Eikermann M, Ferrari MD, van den Maagdenberg AMJM, Moskowitz MA, Ayata C, Eikermann-Haerter K. Inhibition of the P2X7-PANX1 complex suppresses spreading depolarization and neuroinflammation. Brain 2017; 140:1643-1656. [PMID: 28430869 DOI: 10.1093/brain/awx085] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Accepted: 02/12/2017] [Indexed: 01/09/2023] Open
Abstract
Spreading depolarization is a wave of neuronal and glial depolarization. Within minutes after spreading depolarization, the neuronal hemichannel pannexin 1 (PANX1) opens and forms a pore complex with the ligand-gated cation channel P2X7, allowing the release of excitatory neurotransmitters to sustain spreading depolarization and activate neuroinflammation. Here, we explore the hypothesis that the P2X7-PANX1 pore complex is a critical determinant of spreading depolarization susceptibility with important consequences for neuroinflammation and trigeminovascular activation. We found that genetic loss of function or ablation of the P2x7 gene inhibits spreading depolarization. Moreover, pharmacological suppression of the P2X7-PANX1 pore complex inhibits spreading depolarization in mice carrying the human familial hemiplegic migraine type 1 R192Q missense mutation as well as in wild-type mice and rats. Pore inhibitors elevate the electrical threshold for spreading depolarization, and reduce spreading depolarization frequency and amplitude. Pore inhibitors also suppress downstream consequences of spreading depolarization such as upregulation of interleukin-1 beta, inducible nitric oxide synthase and cyclooxygenase-2 in the cortex after spreading depolarization. In addition, they inhibit surrogates for trigeminovascular activation, including expression of calcitonin gene-related peptide in the trigeminal ganglion and c-Fos in the trigeminal nucleus caudalis. Our results are consistent with the hypothesis that the P2X7-PANX1 pore complex is a critical determinant of spreading depolarization susceptibility and its downstream consequences, of potential relevance to its signature disorders such as migraine.
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Affiliation(s)
- Shih-Pin Chen
- Neurovascular Research Lab, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA.,Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan.,Institute of Clinical Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan
| | - Tao Qin
- Neurovascular Research Lab, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Jessica L Seidel
- Neurovascular Research Lab, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Yi Zheng
- Neurovascular Research Lab, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Matthias Eikermann
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, MA and Universitaet Duisburg Essen, Essen, Germany
| | - Michel D Ferrari
- Department of Neurology, Leiden University Medical Centre, 2300 RC Leiden, The Netherlands
| | - Arn M J M van den Maagdenberg
- Department of Neurology, Leiden University Medical Centre, 2300 RC Leiden, The Netherlands.,Department of Human Genetics, Leiden University Medical Centre, 2300 RC Leiden, The Netherlands
| | - Michael A Moskowitz
- Stroke and Neurovascular Regulation Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Cenk Ayata
- Neurovascular Research Lab, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA.,Stroke Service and Neuroscience Intensive Care Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Katharina Eikermann-Haerter
- Neurovascular Research Lab, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
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27
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P2X7 receptor cross-talk regulates ATP-induced pannexin 1 internalization. Biochem J 2017; 474:2133-2144. [PMID: 28495860 DOI: 10.1042/bcj20170257] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 05/04/2017] [Accepted: 05/10/2017] [Indexed: 12/12/2022]
Abstract
In the nervous system, extracellular ATP levels transiently increase in physiological and pathophysiological circumstances, effecting key signalling pathways in plasticity and inflammation through purinergic receptors. Pannexin 1 (Panx1) forms ion- and metabolite-permeable channels that mediate ATP release and are particularly enriched in the nervous system. Our recent study demonstrated that elevation of extracellular ATP triggers Panx1 internalization in a concentration- and time-dependent manner. Notably, this effect was sensitive to inhibition of ionotropic P2X7 purinergic receptors (P2X7Rs). Here, we report our novel findings from the detailed investigation of the mechanism underlying P2X7R-Panx1 cross-talk in ATP-stimulated internalization. We demonstrate that extracellular ATP triggers and is required for the clustering of P2X7Rs and Panx1 on Neuro2a cells through an extracellular physical interaction with the Panx1 first extracellular loop (EL1). Importantly, disruption of P2X7R-Panx1 clustering by mutation of tryptophan 74 within the Panx1 EL1 inhibits Panx1 internalization. Notably, P2X7R-Panx1 clustering and internalization are independent of P2X7R-associated intracellular signalling pathways (Ca2+ influx and Src activation). Further analysis revealed that cholesterol is required for ATP-stimulated P2X7R-Panx1 clustering at the cell periphery. Taken together, our data suggest that extracellular ATP induces and is required for Panx1 EL1-mediated, cholesterol-dependent P2X7R-Panx1 clustering and endocytosis. These findings have important implications for understanding the role of Panx1 in the nervous system and provide important new insights into Panx1-P2X7R cross-talk.
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28
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Molica F, Stierlin FB, Fontana P, Kwak BR. Pannexin- and Connexin-Mediated Intercellular Communication in Platelet Function. Int J Mol Sci 2017; 18:E850. [PMID: 28420171 PMCID: PMC5412434 DOI: 10.3390/ijms18040850] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 04/06/2017] [Accepted: 04/12/2017] [Indexed: 12/11/2022] Open
Abstract
The three major blood cell types, i.e., platelets, erythrocytes and leukocytes, are all produced in the bone marrow. While red blood cells are the most numerous and white cells are the largest, platelets are small fragments and account for a minor part of blood volume. However, platelets display a crucial function by preventing bleeding. Upon vessel wall injury, platelets adhere to exposed extracellular matrix, become activated, and form a platelet plug preventing hemorrhagic events. However, when platelet activation is exacerbated, as in rupture of an atherosclerotic plaque, the same mechanism may lead to acute thrombosis causing major ischemic events such as myocardial infarction or stroke. In the past few years, major progress has been made in understanding of platelet function modulation. In this respect, membrane channels formed by connexins and/or pannexins are of particular interest. While it is still not completely understood whether connexins function as hemichannels or gap junction channels to inhibit platelet aggregation, there is clear-cut evidence for a specific implication of pannexin1 channels in collagen-induced aggregation. The focus of this review is to summarize current knowledge of the role of connexins and pannexins in platelet aggregation and to discuss possible pharmacological approaches along with their limitations and future perspectives for new potential therapies.
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Affiliation(s)
- Filippo Molica
- Department of Pathology and Immunology, University of Geneva, 1211 Geneva, Switzerland.
- Department of Medical Specializations, Cardiology, University of Geneva, 1211 Geneva, Switzerland.
| | - Florian B Stierlin
- Department of Pathology and Immunology, University of Geneva, 1211 Geneva, Switzerland.
- Department of Medical Specializations, Cardiology, University of Geneva, 1211 Geneva, Switzerland.
- Geneva Platelet Group, University of Geneva, 1211 Geneva, Switzerland.
| | - Pierre Fontana
- Geneva Platelet Group, University of Geneva, 1211 Geneva, Switzerland.
- Division of Angiology and Haemostasis, Geneva University Hospitals, 1211 Geneva, Switzerland.
| | - Brenda R Kwak
- Department of Pathology and Immunology, University of Geneva, 1211 Geneva, Switzerland.
- Department of Medical Specializations, Cardiology, University of Geneva, 1211 Geneva, Switzerland.
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29
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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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30
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Seike S, Takehara M, Kobayashi K, Nagahama M. Role of pannexin 1 in Clostridium perfringens beta-toxin-caused cell death. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:3150-3156. [PMID: 27720686 DOI: 10.1016/j.bbamem.2016.10.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 09/30/2016] [Accepted: 10/04/2016] [Indexed: 12/16/2022]
Abstract
BACKGROUND Beta-toxin produced by Clostridium perfringens is a key virulence factor of fatal hemorrhagic enterocolitis and enterotoxemia. This toxin belongs to a family of β-pore-forming toxins (PFTs). We reported recently that the ATP-gated P2X7 receptor interacts with beta-toxin. The ATP-release channel pannexin 1 (Panx1) is an important contributor to P2X7 receptor signaling. Hence, we investigated the involvement of Panx1 in beta-toxin-caused cell death. METHODS We examined the effect of Panx1 in beta-toxin-induced cell death utilizing selective antagonists, knockdown of Panx1, and binding using dot-blot analysis. Localization of Panx1 and the P2X7 receptor after toxin treatment was determined by immunofluorescence staining. RESULTS Selective Panx1 antagonists (carbenoxolone [CBX], probenecid, and Panx1 inhibitory peptide) prevented beta-toxin-caused cell death in THP-1 cells. CBX did not block the binding of the toxin to cells. Small interfering knockdown of Panx1 blocked beta-toxin-mediated cell death through inhibiting the oligomer formation of the toxin. Beta-toxin triggered a transient ATP release from THP-1 cells, but this early ATP release was blocked by CBX. ATP scavengers (apyrase and hexokinase) inhibited beta-toxin-induced cytotoxicity. Furthermore, co-administration of ATP with beta-toxin enhanced the binding and cytotoxicity of the toxin. CONCLUSIONS Based on our results, Panx1 activation is achieved through the interaction of beta-toxin with the P2X7 receptor. Then, ATP released by the Panx1 channel opening promotes oligomer formation of the toxin, leading to cell death. GENERAL SIGNIFICANCE Pannexin 1 is a novel candidate therapeutic target for beta-toxin-mediated disease.
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Affiliation(s)
- Soshi Seike
- Department of Microbiology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho 180, Tokushima 770-8514, Japan
| | - Masaya Takehara
- Department of Microbiology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho 180, Tokushima 770-8514, Japan
| | - Keiko Kobayashi
- Department of Microbiology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho 180, Tokushima 770-8514, Japan
| | - Masahiro Nagahama
- Department of Microbiology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho 180, Tokushima 770-8514, Japan.
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31
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Gajardo-Gómez R, Labra VC, Orellana JA. Connexins and Pannexins: New Insights into Microglial Functions and Dysfunctions. Front Mol Neurosci 2016; 9:86. [PMID: 27713688 PMCID: PMC5031785 DOI: 10.3389/fnmol.2016.00086] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 09/05/2016] [Indexed: 12/11/2022] Open
Abstract
Under physiological conditions, microglia adopt a resting phenotype associated with the production of anti-inflammatory and neurotrophic factors. In response to a wide variety of insults, these cells shift to an activated phenotype that is necessary for the proper restoration of brain homeostasis. However, when the intensity of a threat is relatively high, microglial activation worsens the progression of damage rather than providing protection, with potentially significant consequences for neuronal survival. Coordinated interactions among microglia and other brain cells, including astrocytes and neurons, are critical for the development of timely and optimal inflammatory responses in the brain parenchyma. Tissue synchronization is in part mediated by connexins and pannexins, which are protein families that form different plasma membrane channels to communicate with neighboring cells. Gap junction channels (which are exclusively formed by connexins in vertebrates) connect the cytoplasm of contacting cells to coordinate electrical and metabolic coupling. Hemichannels (HCs) and pannexons (which are formed by connexins and pannexins, respectively) communicate the intra- and extracellular compartments and serve as diffusion pathways for the exchange of ions and small molecules. In this review article, we discuss the available evidence concerning the functional expression and regulation of connexin- and pannexin-based channels in microglia and their contributions to microglial function and dysfunction. Specifically, we focus on the possible implications of these channels in microglia-to-microglia, microglia-to-astrocyte and neuron-to-microglia interactions in the inflamed brain.
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Affiliation(s)
- Rosario Gajardo-Gómez
- Departamento de Neurología, Escuela de Medicina, Pontificia Universidad Católica de Chile Santiago, Chile
| | - Valeria C Labra
- Departamento de Neurología, Escuela de Medicina, Pontificia Universidad Católica de Chile Santiago, Chile
| | - Juan A Orellana
- Departamento de Neurología, Escuela de Medicina, Pontificia Universidad Católica de Chile Santiago, Chile
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Alvarez A, Lagos-Cabré R, Kong M, Cárdenas A, Burgos-Bravo F, Schneider P, Quest AFG, Leyton L. Integrin-mediated transactivation of P2X7R via hemichannel-dependent ATP release stimulates astrocyte migration. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:2175-88. [PMID: 27235833 DOI: 10.1016/j.bbamcr.2016.05.018] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 04/29/2016] [Accepted: 05/23/2016] [Indexed: 01/09/2023]
Abstract
Our previous reports indicate that ligand-induced αVβ3 integrin and Syndecan-4 engagement increases focal adhesion formation and migration of astrocytes. Additionally, ligated integrins trigger ATP release through unknown mechanisms, activating P2X7 receptors (P2X7R), and the uptake of Ca(2+) to promote cell adhesion. However, whether the activation of P2X7R and ATP release are required for astrocyte migration and whether αVβ3 integrin and Syndecan-4 receptors communicate with P2X7R via ATP remains unknown. Here, cells were stimulated with Thy-1, a reported αVβ3 integrin and Syndecan-4 ligand. Results obtained indicate that ATP was released by Thy-1 upon integrin engagement and required the participation of phosphatidylinositol-3-kinase (PI3K), phospholipase-C gamma (PLCγ) and inositol trisphosphate (IP3) receptors (IP3R). IP3R activation leads to increased intracellular Ca(2+), hemichannel (Connexin-43 and Pannexin-1) opening, and ATP release. Moreover, silencing of the P2X7R or addition of hemichannel blockers precluded Thy-1-induced astrocyte migration. Finally, Thy-1 lacking the integrin-binding site did not stimulate ATP release, whereas Thy-1 mutated in the Syndecan-4-binding domain increased ATP release, albeit to a lesser extent and with delayed kinetics compared to wild-type Thy-1. Thus, hemichannels activated downstream of an αVβ3 integrin-PI3K-PLCγ-IP3R pathway are responsible for Thy-1-induced, hemichannel-mediated and Syndecan-4-modulated ATP release that transactivates P2X7Rs to induce Ca(2+) entry. These findings uncover a hitherto unrecognized role for hemichannels in the regulation of astrocyte migration via P2X7R transactivation induced by integrin-mediated ATP release.
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Affiliation(s)
- Alvaro Alvarez
- Cellular Communication Laboratory, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile; Biomedical Neuroscience Institute, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile
| | - Raúl Lagos-Cabré
- Cellular Communication Laboratory, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile; Biomedical Neuroscience Institute, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile
| | - Milene Kong
- Cellular Communication Laboratory, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile; Biomedical Neuroscience Institute, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile
| | - Areli Cárdenas
- Cellular Communication Laboratory, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile; Biomedical Neuroscience Institute, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile
| | - Francesca Burgos-Bravo
- Cellular Communication Laboratory, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile; Biomedical Neuroscience Institute, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile
| | - Pascal Schneider
- Department of Biochemistry, University of Lausanne, 1066 Epalinges, Switzerland
| | - Andrew F G Quest
- Cellular Communication Laboratory, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile; Advanced Center for Chronic Diseases, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile; Biomedical Neuroscience Institute, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile
| | - Lisette Leyton
- Cellular Communication Laboratory, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile; Advanced Center for Chronic Diseases, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile; Biomedical Neuroscience Institute, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile.
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33
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Tewari D, Mukhopadhyay M, Nekkanti MS, Vallabhaneni S, Sahu G, Jetti SK, Preethidan D, Bera AK. Cytoprotective effect of Centella asiatica is mediated through the modulation of mitochondrial voltage-dependent anion channel (VDAC) and scavenging of free radicals. J Funct Foods 2016. [DOI: 10.1016/j.jff.2015.11.047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Mahaut-Smith MP, Taylor KA, Evans RJ. Calcium Signalling through Ligand-Gated Ion Channels such as P2X1 Receptors in the Platelet and other Non-Excitable Cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 898:305-29. [PMID: 27161234 DOI: 10.1007/978-3-319-26974-0_13] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Ligand-gated ion channels on the cell surface are directly activated by the binding of an agonist to their extracellular domain and often referred to as ionotropic receptors. P2X receptors are ligand-gated non-selective cation channels with significant permeability to Ca(2+) whose principal physiological agonist is ATP. This chapter focuses on the mechanisms by which P2X1 receptors, a ubiquitously expressed member of the family of ATP-gated channels, can contribute to cellular responses in non-excitable cells. Much of the detailed information on the contribution of P2X1 to Ca(2+) signalling and downstream functional events has been derived from the platelet. The underlying primary P2X1-generated signalling event in non-excitable cells is principally due to Ca(2+) influx, although Na(+) entry will also occur along with membrane depolarization. P2X1 receptor stimulation can lead to additional Ca(2+) mobilization via a range of routes such as amplification of G-protein-coupled receptor-dependent Ca(2+) responses. This chapter also considers the mechanism by which cells generate extracellular ATP for autocrine or paracrine activation of P2X1 receptors. For example cytosolic ATP efflux can result from opening of pannexin anion-permeable channels or following damage to the cell membrane. Alternatively, ATP stored in specialised secretory vesicles can undergo quantal release via the process of exocytosis. Examples of physiological or pathophysiological roles of P2X1-dependent signalling in non-excitable cells are also discussed, such as thrombosis and immune responses.
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Affiliation(s)
- Martyn P Mahaut-Smith
- Department of Molecular and Cell Biology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester, LE1 9HN, UK.
| | - Kirk A Taylor
- Department of Biomedical and Forensic Sciences, Anglia Ruskin University, Cambridge, UK
| | - Richard J Evans
- Department of Molecular and Cell Biology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester, LE1 9HN, UK
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Mittal R, Chan B, Grati M, Mittal J, Patel K, Debs LH, Patel AP, Yan D, Chapagain P, Liu XZ. Molecular Structure and Regulation of P2X Receptors With a Special Emphasis on the Role of P2X2 in the Auditory System. J Cell Physiol 2015; 231:1656-70. [PMID: 26627116 DOI: 10.1002/jcp.25274] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 12/01/2015] [Indexed: 12/23/2022]
Abstract
The P2X purinergic receptors are cation-selective channels gated by extracellular adenosine 5'-triphosphate (ATP). These purinergic receptors are found in virtually all mammalian cell types and facilitate a number of important physiological processes. Within the past few years, the characterization of crystal structures of the zebrafish P2X4 receptor in its closed and open states has provided critical insights into the mechanisms of ligand binding and channel activation. Understanding of this gating mechanism has facilitated to design and interpret new modeling and structure-function experiments to better elucidate how different agonists and antagonists can affect the receptor with differing levels of potency. This review summarizes the current knowledge on the structure, activation, allosteric modulators, function, and location of the different P2X receptors. Moreover, an emphasis on the P2X2 receptors has been placed in respect to its role in the auditory system. In particular, the discovery of three missense mutations in P2X2 receptors could become important areas of study in the field of gene therapy to treat progressive and noise-induced hearing loss. J. Cell. Physiol. 231: 1656-1670, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Rahul Mittal
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida
| | - Brandon Chan
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida
| | - M'hamed Grati
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida
| | - Jeenu Mittal
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida
| | - Kunal Patel
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida
| | - Luca H Debs
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida
| | - Amit P Patel
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida
| | - Denise Yan
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida
| | - Prem Chapagain
- Department of Physics, Florida International University, Miami, Florida.,Biomolecular Science Institute, Florida International University, Miami, Florida
| | - Xue Zhong Liu
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida.,Department of Human Genetics, University of Miami Miller School of Medicine, Miami, Florida.,Department of Biochemistry, University of Miami Miller School of Medicine, Miami, Florida
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Emerging role of P2X7 receptors in CNS health and disease. Ageing Res Rev 2015; 24:328-42. [PMID: 26478005 DOI: 10.1016/j.arr.2015.10.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Accepted: 10/05/2015] [Indexed: 12/11/2022]
Abstract
Purinergic signalling in the brain is becoming an important focus in the study of CNS health and disease. Various purinergic receptors are found to be present in different brain cells in varying extent, which get activated upon binding of ATP or its analogues. Conventionally, ATP was considered only as a major metabolic fuel of the cell but its recognition as a neurotransmitter in early 1970s, brought meaningful insights in neuron glia crosstalk, participating in various physiological functions in the brain. P2X7R, a member of ligand gated purinergic receptor (P2X) family, is gaining attention in the field of neuroscience because of its emerging role in broad spectrum of ageing and age related neurological disorders. The aim of this review is to provide an overview about the structure and function of P2X7R highlighting its unique features which distinguish it from the other members of its family. This review critically analyzes the literature mentioning the details about the agonist and antagonist of the P2X7R. It also emphasizes the advancements in understanding the dual role of P2X7R in brain development and disorders inviting meaningful insights about its involvement in Alzheimer's disease, Huntington's disease, Multiple Sclerosis, Neuropathic pain, Spinal Cord Injury and NeuroAIDS. Exploring the roles of P2X7R in detail is critical to identify its therapeutic potential in the treatment of acute and chronic neurodegenerative diseases. Moreover, this review also helps to raise more interest in the neurobiology of the purinergic receptors and thus providing new avenues for future research.
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Glass BJ, Hu RG, Phillips ARJ, Becker DL. The action of mimetic peptides on connexins protects fibroblasts from the negative effects of ischemia reperfusion. Biol Open 2015; 4:1473-80. [PMID: 26471768 PMCID: PMC4728352 DOI: 10.1242/bio.013573] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Connexins have been proposed as a target for therapeutic treatment of a variety of conditions. The main approaches have been by antisense or small peptides specific against connexins. Some of these peptides enhance communication while others interfere with connexin binding partners or bind to the intracellular and extracellular loops of connexins. Here, we explored the mechanism of action of a connexin mimetic peptide by evaluating its effect on gap junction channels, connexin protein levels and hemichannel activity in fibroblast cells under normal conditions and following ischemia reperfusion injury which elevates Cx43 levels, increases hemichannel activity and causes cell death. Our results showed that the effects of the mimetic peptide were concentration-dependent. High concentrations (100-300 μM) significantly reduced Cx43 protein levels and GJIC within 2 h, while these effects did not appear until 6 h when using lower concentrations (10-30 μM). Cell death can be reduced when hemichannel opening and GJIC were minimised. Summary: Connexin mimetic peptides can reduce the levels of connexin proteins in cells and can prevent the spread of cell death that occurs following ischemia reperfusion injury, which has therapeutic potential.
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Affiliation(s)
- Beverley J Glass
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Rebecca G Hu
- Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Singapore 308232
| | - Anthony R J Phillips
- CoDa Therapeutics, Inc., 10 College Hill Road, Herne Bay, Auckland 1011, New Zealand School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand
| | - David L Becker
- Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Singapore 308232
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Abstract
Piezo proteins (Piezo1 and Piezo2) are recently identified mechanically activated cation channels in eukaryotic cells and associated with physiological responses to touch, pressure, and stretch. In particular, human RBCs express Piezo1 on their membranes, and mutations of Piezo1 have been linked to hereditary xerocytosis. To date, however, physiological functions of Piezo1 on normal RBCs remain poorly understood. Here, we show that Piezo1 regulates mechanotransductive release of ATP from human RBCs by controlling the shear-induced calcium (Ca(2+)) influx. We find that, in human RBCs treated with Piezo1 inhibitors or having mutant Piezo1 channels, the amounts of shear-induced ATP release and Ca(2+) influx decrease significantly. Remarkably, a critical extracellular Ca(2+) concentration is required to trigger significant ATP release, but membrane-associated ATP pools in RBCs also contribute to the release of ATP. Our results show how Piezo1 channels are likely to function in normal RBCs and suggest a previously unidentified mechanotransductive pathway in ATP release. Thus, we anticipate that the study will impact broadly on the research of red cells, cellular mechanosensing, and clinical studies related to red cell disorders and vascular disease.
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Barros-Barbosa AR, Lobo MG, Ferreirinha F, Correia-de-Sá P, Cordeiro JM. P2X7 receptor activation downmodulates Na(+)-dependent high-affinity GABA and glutamate transport into rat brain cortex synaptosomes. Neuroscience 2015; 306:74-90. [PMID: 26299340 DOI: 10.1016/j.neuroscience.2015.08.026] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 08/09/2015] [Accepted: 08/13/2015] [Indexed: 02/06/2023]
Abstract
Sodium-dependent high-affinity amino-acid transporters play crucial roles in terminating synaptic transmission in the central nervous system (CNS). However, there is lack of information about the mechanisms underlying the regulation of amino-acid transport by fast-acting neuromodulators, like ATP. Here, we investigated whether activation of the ATP-sensitive P2X7 receptor modulates Na(+)-dependent high-affinity γ-aminobutyric acid (GABA) and glutamate uptake into nerve terminals (synaptosomes) of the rat cerebral cortex. Radiolabeled neurotransmitter accumulation was evaluated by liquid scintillation spectrometry. The cell-permeant sodium-selective fluorescent indicator, SBFI-AM, was used to estimate Na(+) influx across plasma membrane. 2'(3')-O-(4-benzoylbenzoyl)ATP (BzATP, 3-300 μM), a prototypic P2X7 receptor agonist, concentration-dependently decreased [(3)H]GABA (14%) and [(14)C]glutamate (24%) uptake; BzATP decreased transport maximum velocity (Vmax) without affecting the Michaelis constant (Km) values. The selective P2X7 receptor antagonist, A-438079 (3 μM), prevented inhibition of [(3)H]GABA and [(14)C]glutamate uptake by BzATP (100 μM). The inhibitory effect of BzATP coincided with its ability to increase intracellular Na(+) and was mimicked by Na(+) ionophores, like gramicidin and monensin. Increases in intracellular Na(+) (with veratridine or ouabain) or substitution of extracellular Na(+) by N-methyl-D-glucamine (NMDG)(+) all decreased [(3)H]GABA and [(14)C]glutamate uptake and attenuated BzATP effects. Uptake inhibition by BzATP (100 μM) was also attenuated by calmidazolium, which selectively inhibits Na(+) currents through the P2X7 receptor pore. In conclusion, disruption of the Na(+) gradient by P2X7 receptor activation downmodulates high-affinity GABA and glutamate uptake into rat cortical synaptosomes. Interference with amino-acid transport efficacy may constitute a novel target for therapeutic management of cortical excitability.
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Affiliation(s)
- A R Barros-Barbosa
- Laboratório de Farmacologia e Neurobiologia, Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto (UP), Porto, Portugal; Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto (UP), Porto, Portugal
| | - M G Lobo
- Laboratório de Farmacologia e Neurobiologia, Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto (UP), Porto, Portugal; Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto (UP), Porto, Portugal
| | - F Ferreirinha
- Laboratório de Farmacologia e Neurobiologia, Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto (UP), Porto, Portugal; Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto (UP), Porto, Portugal
| | - P Correia-de-Sá
- Laboratório de Farmacologia e Neurobiologia, Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto (UP), Porto, Portugal; Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto (UP), Porto, Portugal.
| | - J M Cordeiro
- Laboratório de Farmacologia e Neurobiologia, Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto (UP), Porto, Portugal; Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto (UP), Porto, Portugal.
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Bravo D, Maturana CJ, Pelissier T, Hernández A, Constandil L. Interactions of pannexin 1 with NMDA and P2X7 receptors in central nervous system pathologies: Possible role on chronic pain. Pharmacol Res 2015. [PMID: 26211949 DOI: 10.1016/j.phrs.2015.07.016] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Pannexin 1 (Panx1) is a glycoprotein that acts as a membrane channel in a wide variety of tissues in mammals. In the central nervous system (CNS) Panx1 is expressed in neurons, astrocytes and microglia, participating in the pathophysiology of some CNS diseases, such as epilepsy, anoxic depolarization after stroke and neuroinflammation. In these conditions Panx1 acts as an important modulator of the neuroinflammatory response, by secreting ATP, by interacting with the P2X7 receptor (P2X7R), and as an amplifier of NMDA receptor (NMDAR) currents, particularly in conditions of pathological neuronal hyperexcitability. Here, we briefly reviewed the current evidences that support the interaction of Panx1 with NMDAR and P2X7R in pathological contexts of the CNS, with special focus in recent data supporting that Panx1 is involved in chronic pain signaling by interacting with NMDAR in neurons and with P2X7R in glia. The participation of Panx1 in chronic pain constitutes a novel topic for research in the field of clinical neurosciences and a potential target for pharmacological interventions in chronic pain.
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Affiliation(s)
- D Bravo
- Laboratory of Neurobiology, Department of Biology, Faculty of Chemistry and Biology, University of Santiago of Chile, Chile; School of Kinesiology, Faculty of Sport, Health and Recreation, University Bernardo O'Higgins, Chile.
| | - C J Maturana
- Departamento de Fisiología, Pontificia Universidad Católica De Chile, Chile
| | - T Pelissier
- Program of Molecular and Clinical Pharmacology, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Chile
| | - A Hernández
- Laboratory of Neurobiology, Department of Biology, Faculty of Chemistry and Biology, University of Santiago of Chile, Chile
| | - L Constandil
- Laboratory of Neurobiology, Department of Biology, Faculty of Chemistry and Biology, University of Santiago of Chile, Chile
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Li L, He L, Wu D, Chen L, Jiang Z. Pannexin-1 channels and their emerging functions in cardiovascular diseases. Acta Biochim Biophys Sin (Shanghai) 2015; 47:391-6. [PMID: 25921414 DOI: 10.1093/abbs/gmv028] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Accepted: 02/04/2015] [Indexed: 11/15/2022] Open
Abstract
Pannexin-1, Pannexin-2, and Pannexin-3 are three members of the Pannexin family of channel-forming glycoprotein. Their primary function is defined by their ability to form single-membrane channels. Pannexin-1 ubiquitously exists in many cells and organs throughout the body and is specially distributed in the circulatory system, while the expressions of Pannexin-2 and Pannexin-3 are mostly restricted to organs and tissues. Pannexin-1 oligomers have been shown to be functional single membrane channels that connect intracellular and extracellular compartments and are not intercellular channels in appositional membranes. The physiological functions of Pannexin-1 are to link to the adenosine triphosphate efflux that acts as a paracrine signal, and regulate cellular inflammasomes in a variety of cell types under physiological and pathophysiological conditions. However, there are still many functions to be explored. This review summarizes recent reports and discusses the role of Pannexin-1 in cardiovascular diseases, including ischemia, arrhythmia, cardiac fibrosis, and hypertension. Pannexin-1 has been suggested as an exciting, clinically relevant target in cardiovascular diseases.
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Affiliation(s)
- Lanfang Li
- Post-doctoral Mobile Stations for Basic Medicine, Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, University of South China, Hengyang 421001, China Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, University of South China, Hengyang 421001, China
| | - Lu He
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, University of South China, Hengyang 421001, China
| | - Di Wu
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, University of South China, Hengyang 421001, China
| | - Linxi Chen
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, University of South China, Hengyang 421001, China
| | - Zhisheng Jiang
- Post-doctoral Mobile Stations for Basic Medicine, Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, University of South China, Hengyang 421001, China
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Poornima V, Vallabhaneni S, Mukhopadhyay M, Bera AK. Nitric oxide inhibits the pannexin 1 channel through a cGMP-PKG dependent pathway. Nitric Oxide 2015; 47:77-84. [PMID: 25917852 DOI: 10.1016/j.niox.2015.04.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 04/15/2015] [Accepted: 04/17/2015] [Indexed: 11/16/2022]
Abstract
Nitric oxide (NO), a major gaseous signaling molecule, modulates several ion channels and receptors. Here we show that NO attenuates pannexin 1 (Panx1) mediated currents in HEK-293 cells. NO exerts its effect by activating a cGMP-protein kinase G (PKG) dependent pathway. NO donors, sodium nitroprusside (SNP), S-nitroso-N-acetylpenicillamine (SNAP) and S-nitrosoglutathione (GSNO), reduced Panx1 currents by 25-41%. 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), an inhibitor of soluble guanylyl cyclase (sGC), blocked the inhibition completely, whereas sGC activator YC-1 mimicked the effect of NO, suggesting the involvement of a cGMP dependent pathway. Supporting this, NO had no effect in the presence of the PKG inhibitor, KT5823. Further, immuno-precipitated Panx1 was recognized by an anti-phosphoserine antibody in Western blot. Phosphorylation was enhanced significantly when cells were treated with SNP. The target for phosphorylation is possibly Ser 206 of Panx1, as its mutation to Ala completely abolished the NO mediated inhibition.
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Affiliation(s)
- V Poornima
- Department of Biotechnology, Bhupat & Jyoti Mehta School of BioSciences, Indian Institute of Technology Madras, Sardar Patel Road, Chennai, Tamil Nadu 600036, India
| | - Sirisha Vallabhaneni
- Department of Biotechnology, Bhupat & Jyoti Mehta School of BioSciences, Indian Institute of Technology Madras, Sardar Patel Road, Chennai, Tamil Nadu 600036, India
| | - Mohona Mukhopadhyay
- Department of Biotechnology, Bhupat & Jyoti Mehta School of BioSciences, Indian Institute of Technology Madras, Sardar Patel Road, Chennai, Tamil Nadu 600036, India
| | - Amal Kanti Bera
- Department of Biotechnology, Bhupat & Jyoti Mehta School of BioSciences, Indian Institute of Technology Madras, Sardar Patel Road, Chennai, Tamil Nadu 600036, India.
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Modulation of microglial process convergence toward neuronal dendrites by extracellular calcium. J Neurosci 2015; 35:2417-22. [PMID: 25673836 DOI: 10.1523/jneurosci.3279-14.2015] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Extracellular calcium concentrations in the brain fluctuate during neuronal activities and may affect the behavior of brain cells. Microglia are highly dynamic immune cells of the brain. However, the effects of extracellular calcium concentrations on microglial dynamics have not been investigated. Here, we addressed this question in mouse brain slices and in vivo using two-photon microscopy. We serendipitously found that extracellular calcium reduction induced microglial processes to converge at distinct sites, a phenomenon we termed microglial process convergence (MPCs). Our studies revealed that MPCs target neuronal dendrites independent of neuronal action potential firing and is mediated by ATP release and microglial P2Y12 receptors. These results indicate that microglia monitor and interact with neurons during conditions of cerebral calcium reduction in the normal and diseased brain.
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Novel Mechanisms of Herbal Therapies for Inhibiting HMGB1 Secretion or Action. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2015; 2015:456305. [PMID: 25821489 PMCID: PMC4363608 DOI: 10.1155/2015/456305] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 09/24/2014] [Accepted: 10/01/2014] [Indexed: 12/11/2022]
Abstract
High mobility group box 1 (HMGB1) is an evolutionarily conserved protein and is constitutively expressed in virtually all types of cells. In response to microbial infections, HMGB1 is secreted from activated immune cells to orchestrate rigorous inflammatory responses. Here we review the distinct mechanisms by which several herbal components inhibit HMGB1 action or secretion, such as by modulating inflammasome activation, autophagic degradation, or endocytic uptake. In light of the reciprocal interactions between these cellular processes, it is possible to develop more effective combinational herbal therapies for the clinical management of inflammatory diseases.
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Kaneko Y, Tachikawa M, Akaogi R, Fujimoto K, Ishibashi M, Uchida Y, Couraud PO, Ohtsuki S, Hosoya KI, Terasaki T. Contribution of pannexin 1 and connexin 43 hemichannels to extracellular calcium-dependent transport dynamics in human blood-brain barrier endothelial cells. J Pharmacol Exp Ther 2015; 353:192-200. [PMID: 25670633 DOI: 10.1124/jpet.114.220210] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Dysregulation of blood-brain barrier (BBB) transport function is thought to exacerbate neuronal damage in acute ischemic stroke. The purpose of this study was to clarify the characteristics of pannexin (Px) and/or connexin (Cx) hemichannel(s)-mediated transport of organic anions and cations in human BBB endothelial cell line hCMEC/D3 and to identify inhibitors of hemichannel opening in hCMEC/D3 cells in the absence of extracellular Ca(2+), a condition mimicking acute ischemic stroke. In the absence of extracellular Ca(2+), the cells showed increased uptake and efflux transport of organic ionic fluorescent dyes. Classic hemichannel inhibitors markedly inhibited the enhanced uptake and efflux. Quantitative targeted absolute proteomics confirmed Px1 and Cx43 protein expression in plasma membrane of hCMEC/D3 cells. Knockdown of Px1 and Cx43 with the small interfering RNAs significantly inhibited the enhanced uptake and efflux of organic anionic and cationic fluorescent dyes. Clinically used cilnidipine and progesterone, which have neuroprotective effects in animal ischemia models, were identified as inhibitors of hemichannel opening. These findings suggest that altered transport dynamics at the human BBB in the absence of extracellular Ca(2+) is at least partly attributable to opening of Px1 and Cx43 hemichannels. Therefore, we speculate that Px1 and Cx43 may be potential drug targets to ameliorate BBB transport dysregulation during acute ischemia.
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Affiliation(s)
- Yosuke Kaneko
- Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (Y.K., M.T., R.A., Y.U., T.T.); Department of Applied Chemistry and Biochemistry, Faculty of Engineering, Kyushu Sangyo University, Fukuoka, Japan (K.F., M.I.); INSERM, U1016, Institut Cochin and CNRS, UMR8104, and Université Paris Descartes, Paris, France (P.-O.C.); Department of Pharmaceutical Microbiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan (S.O.); and Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (K.H.)
| | - Masanori Tachikawa
- Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (Y.K., M.T., R.A., Y.U., T.T.); Department of Applied Chemistry and Biochemistry, Faculty of Engineering, Kyushu Sangyo University, Fukuoka, Japan (K.F., M.I.); INSERM, U1016, Institut Cochin and CNRS, UMR8104, and Université Paris Descartes, Paris, France (P.-O.C.); Department of Pharmaceutical Microbiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan (S.O.); and Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (K.H.)
| | - Ryo Akaogi
- Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (Y.K., M.T., R.A., Y.U., T.T.); Department of Applied Chemistry and Biochemistry, Faculty of Engineering, Kyushu Sangyo University, Fukuoka, Japan (K.F., M.I.); INSERM, U1016, Institut Cochin and CNRS, UMR8104, and Université Paris Descartes, Paris, France (P.-O.C.); Department of Pharmaceutical Microbiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan (S.O.); and Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (K.H.)
| | - Kazuhisa Fujimoto
- Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (Y.K., M.T., R.A., Y.U., T.T.); Department of Applied Chemistry and Biochemistry, Faculty of Engineering, Kyushu Sangyo University, Fukuoka, Japan (K.F., M.I.); INSERM, U1016, Institut Cochin and CNRS, UMR8104, and Université Paris Descartes, Paris, France (P.-O.C.); Department of Pharmaceutical Microbiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan (S.O.); and Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (K.H.)
| | - Megumi Ishibashi
- Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (Y.K., M.T., R.A., Y.U., T.T.); Department of Applied Chemistry and Biochemistry, Faculty of Engineering, Kyushu Sangyo University, Fukuoka, Japan (K.F., M.I.); INSERM, U1016, Institut Cochin and CNRS, UMR8104, and Université Paris Descartes, Paris, France (P.-O.C.); Department of Pharmaceutical Microbiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan (S.O.); and Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (K.H.)
| | - Yasuo Uchida
- Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (Y.K., M.T., R.A., Y.U., T.T.); Department of Applied Chemistry and Biochemistry, Faculty of Engineering, Kyushu Sangyo University, Fukuoka, Japan (K.F., M.I.); INSERM, U1016, Institut Cochin and CNRS, UMR8104, and Université Paris Descartes, Paris, France (P.-O.C.); Department of Pharmaceutical Microbiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan (S.O.); and Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (K.H.)
| | - Pierre-Olivier Couraud
- Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (Y.K., M.T., R.A., Y.U., T.T.); Department of Applied Chemistry and Biochemistry, Faculty of Engineering, Kyushu Sangyo University, Fukuoka, Japan (K.F., M.I.); INSERM, U1016, Institut Cochin and CNRS, UMR8104, and Université Paris Descartes, Paris, France (P.-O.C.); Department of Pharmaceutical Microbiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan (S.O.); and Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (K.H.)
| | - Sumio Ohtsuki
- Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (Y.K., M.T., R.A., Y.U., T.T.); Department of Applied Chemistry and Biochemistry, Faculty of Engineering, Kyushu Sangyo University, Fukuoka, Japan (K.F., M.I.); INSERM, U1016, Institut Cochin and CNRS, UMR8104, and Université Paris Descartes, Paris, France (P.-O.C.); Department of Pharmaceutical Microbiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan (S.O.); and Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (K.H.)
| | - Ken-ichi Hosoya
- Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (Y.K., M.T., R.A., Y.U., T.T.); Department of Applied Chemistry and Biochemistry, Faculty of Engineering, Kyushu Sangyo University, Fukuoka, Japan (K.F., M.I.); INSERM, U1016, Institut Cochin and CNRS, UMR8104, and Université Paris Descartes, Paris, France (P.-O.C.); Department of Pharmaceutical Microbiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan (S.O.); and Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (K.H.)
| | - Tetsuya Terasaki
- Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (Y.K., M.T., R.A., Y.U., T.T.); Department of Applied Chemistry and Biochemistry, Faculty of Engineering, Kyushu Sangyo University, Fukuoka, Japan (K.F., M.I.); INSERM, U1016, Institut Cochin and CNRS, UMR8104, and Université Paris Descartes, Paris, France (P.-O.C.); Department of Pharmaceutical Microbiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan (S.O.); and Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (K.H.)
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46
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Bao GQ, He L, Lee D, D'Angelo J, Wang HC. An ongoing search for potential targets and therapies for lethal sepsis. Mil Med Res 2015; 2:20. [PMID: 26257917 PMCID: PMC4529709 DOI: 10.1186/s40779-015-0047-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 07/20/2015] [Indexed: 01/15/2023] Open
Abstract
Sepsis, which refers to a systemic inflammatory response syndrome resulting from a microbial infection, represents the leading cause of death in intensive care units. The pathogenesis of sepsis remains poorly understood although it is attributable to dysregulated immune responses orchestrated by innate immune cells that are sequentially released early (e.g., tumor necrosis factor(TNF), interleukin-1(IL-1), and interferon-γ(IFN-γ)) and late (e.g., high mobility group box 1(HMGB1)) pro-inflammatory mediators. As a ubiquitous nuclear protein, HMGB1 can be passively released from pathologically damaged cells, thereby converging infection and injury on commonly dysregulated inflammatory responses. We review evidence that supports extracellular HMGB1 as a late mediator of inflammatory diseases and discuss the potential of several Chinese herbal components as HMGB1-targeting therapies. We propose that it is important to develop strategies for specifically attenuating injury-elicited inflammatory responses without compromising the infection-mediated innate immunity for the clinical management of sepsis and other inflammatory diseases.
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Affiliation(s)
- Guo-Qiang Bao
- Department of Emergency Medicine, North Shore University Hospital, Manhasset, NY 11030 USA.,The Feinstein Institute for Medical Research, 350 Community Drive, Manhasset, NY 11030 USA.,Department of General Surgery, Tangdu Hospital, The 4th Military Medical University, Xi'an, Shaanxi 710032 China
| | - Li He
- Department of Ophthalmology, University of Alabama at Birmingham, Birmingham, AL 35294 USA
| | - David Lee
- Department of Emergency Medicine, North Shore University Hospital, Manhasset, NY 11030 USA
| | - John D'Angelo
- Department of Emergency Medicine, North Shore University Hospital, Manhasset, NY 11030 USA
| | - Hai-Chao Wang
- Department of Emergency Medicine, North Shore University Hospital, Manhasset, NY 11030 USA.,The Feinstein Institute for Medical Research, 350 Community Drive, Manhasset, NY 11030 USA
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Davidson J, Green C, Bennet L, Gunn A. Battle of the hemichannels – Connexins and Pannexins in ischemic brain injury. Int J Dev Neurosci 2014; 45:66-74. [DOI: 10.1016/j.ijdevneu.2014.12.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 12/19/2014] [Accepted: 12/19/2014] [Indexed: 12/20/2022] Open
Affiliation(s)
- J.O. Davidson
- Department of PhysiologyThe University of AucklandAucklandNew Zealand
| | - C.R. Green
- Department of OphthalmologyThe University of AucklandAucklandNew Zealand
| | - L. Bennet
- Department of PhysiologyThe University of AucklandAucklandNew Zealand
| | - A.J. Gunn
- Department of PhysiologyThe University of AucklandAucklandNew Zealand
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48
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Schneider SL, Ross AL, Grichnik JM. Do inflammatory pathways drive melanomagenesis? Exp Dermatol 2014; 24:86-90. [PMID: 25041143 DOI: 10.1111/exd.12502] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/13/2014] [Indexed: 12/12/2022]
Abstract
Inflammatory pathways serve to protect the host and promote tissue healing/repair; however, over-activation or dysregulation can be pathological with unintended consequences including malignant progression. A correlation between inflammation and cancer has been well established, and anti-inflammatory medications have been shown to be chemopreventive in certain malignancies. Data are now becoming available that outline an inflammatory pathway that may have a critical role in melanomagenesis. ATP-regulated membrane channels/receptors P2X7 and PANX1 have been directly implicated in melanoma tumor growth. Among other potential effects, opening of the P2X7/PANX1 channel results in activation of the NALP3 inflammasome, which in turn leads to caspase-1 activation and increased levels of activated IL-1β. Elevated levels of caspase-1 and IL-1β have been correlated with melanoma progression, and inhibitors of the inflammasome, caspase and IL-1β activity have all been shown to inhibit melanoma growth. Among many other potential actions, IL-1β increases cyclooxygenase-2 expression leading to local increases in inflammatory mediators such as prostaglandin E2 (PGE2). Anti-inflammatory medications targeting the end of this pathway have had positive results for certain cancers but overall remain mixed for melanoma. A better understanding of the pathways and appropriate intervention points may help direct future therapies. In this viewpoint, we will review data and attempt to model an inflammatory pathway that may be critical for melanomagenesis and propose future directions for exploration.
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Affiliation(s)
- Samantha L Schneider
- Department of Dermatology and Cutaneous Surgery, Miller School of Medicine, University of Miami, Miami, FL, USA; Albert Einstein College of Medicine, Bronx, NY, USA
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Vavilala DT, Reddy S, Sachchidanand, Prakash S, Ponnaluri VKC, Kumar A, Mukherji M. Prohexadione, a plant growth regulator, inhibits histone lysine demethylases and modulates epigenetics. Toxicol Rep 2014; 1:1152-1161. [PMID: 28962325 PMCID: PMC5598483 DOI: 10.1016/j.toxrep.2014.10.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 10/11/2014] [Accepted: 10/25/2014] [Indexed: 12/25/2022] Open
Abstract
Background Epigenetic modifications, particularly DNA methylation and posttranslational histone modifications regulate heritable changes in transcription without changes in the DNA sequence. Despite a number of studies showing clear links between environmental factors and DNA methylation, little is known about the effect of environmental factors on the recently identified histone lysine methylation. Since their identification numerous studies have establish critical role played by these enzymes in mammalian development. Objectives Identification of the Jumonji (Jmj) domain containing histone lysine demethylase have added a new dimension to epigenetic control of gene expression by dynamic regulation of histone methylation marks. The objective of our study was to evaluate the effect of prohexadione and trinexapac, widely used plant growth regulators of the acylcyclohexanediones class, on the enzymatic activity of histone lysine demethylases and histone modifications during the neural stem/progenitor cell differentiation. Methods Here we show that prohexadione, but not trinexapac, directly inhibits non-heme iron (II), 2-oxoglutarate-dependent histone lysine demethylase such as Jmjd2a. We used molecular modeling to show binding of prohexadione to Jmjd2a. We also performed in vitro demethylation assays to show the inhibitory effect of prohexadione on Jmjd2a. Further we tested this molecule in cell culture model of mouse hippocampal neural stem/progenitor cells to demonstrate its effect toward neuronal proliferation and differentiation. Results Molecular modeling studies suggest that prohexadione binds to the 2-oxoglutarate binding site of Jmjd2a demethylase. Treatment of primary neural stem/progenitor cells with prohexadione showed a concentration dependent reduction in their proliferation. Further, the prohexadione treated neurospheres were induced toward neurogenic lineage upon differentiation. Conclusions Our results describe an important chemico-biological interaction of prohexadione, in light of critical roles played by histone lysine demethylases in human health and diseases.
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Affiliation(s)
- Divya Teja Vavilala
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, MO 64108, USA
| | - Sujatha Reddy
- Centre for Cellular and Molecular Biology, Hyderabad 500007, Andhra Pradesh, India
| | - Sachchidanand
- National Institute of Pharmaceutical Education & Research (NIPER), Hajipur 844101, Bihar, India
| | - Swami Prakash
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, MO 64108, USA
| | - V K Chaithanya Ponnaluri
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, MO 64108, USA
| | - Arvind Kumar
- Centre for Cellular and Molecular Biology, Hyderabad 500007, Andhra Pradesh, India
| | - Mridul Mukherji
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, MO 64108, USA
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50
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da Silva MV, Marosti AR, Mendes CE, Palombit K, Castelucci P. Differential effects of experimental ulcerative colitis on P2X7 receptor expression in enteric neurons. Histochem Cell Biol 2014; 143:171-84. [PMID: 25201348 DOI: 10.1007/s00418-014-1270-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/26/2014] [Indexed: 12/17/2022]
Abstract
The digestive tracts of ulcerative colitis and Crohn's disease patients present with pathophysiological processes and intestinal necrosis. This study examined the P2X7 receptor and changes in the distal colon in enteric neurons of rats with experimental ulcerative colitis. The analysis was performed in the distal colons of rats with ulcerative colitis induced by the administration of 2,4,6-trinitrobenzene sulfonic acid (colitis group). The survival time after colitis induction was 24 h. The treated animals were compared to sham rats injected with phosphate-buffered saline and to animals with no intervention (control group). Tissues were prepared for immunohistochemical double-staining methods to examine P2X7 receptor, choline acetyltransferase (ChAT), calbindin, calretinin, anti-HuC/D (pan-neuronal) and S100β (pan-glial). The colocalization of the P2X7 receptor-immunoreactive (IR) cells was observed in the myenteric plexus with nitric oxide synthase (NOS)-, ChAT-,calbindin-, calretinin- and HuC/D-IR neurons and S100β-IR cells in the control, sham and colitis groups. The neuronal density (cell bodies/cm(2)) decreased in the myenteric plexus by 11, 18, 34, 22 and 60% in the P2X7 receptor, NOS-, ChAT-, calbindin- and calretinin-IR neurons, respectively. In addition, the densities (cell bodies/cm(2)) of HuC/D-IR neurons and S100β-IR enteric glial cells decreased by 33 and 29%, respectively. The profile areas were reduced by 6.8 and 21% in NOS- and ChAT-IR neurons, respectively. There was also a 20% increase of calbindin-IR neurons. Morphological changes were observed, such as increased neutrophils, disintegration of the intestinal epithelium and goblet cells and decreased collagen. This study demonstrated that colitis differentially affects P2X7 receptor-expressing enteric neurons based on their chemical codes and may cause changes in morphology and motility.
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Affiliation(s)
- Marcos Vinícius da Silva
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Dr. Lineu Prestes, 2415, São Paulo, CEP 05508-900, Brazil
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