1
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Planas AM. Role of microglia in stroke. Glia 2024; 72:1016-1053. [PMID: 38173414 DOI: 10.1002/glia.24501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 12/07/2023] [Accepted: 12/19/2023] [Indexed: 01/05/2024]
Abstract
Microglia play key roles in the post-ischemic inflammatory response and damaged tissue removal reacting rapidly to the disturbances caused by ischemia and working to restore the lost homeostasis. However, the modified environment, encompassing ionic imbalances, disruption of crucial neuron-microglia interactions, spreading depolarization, and generation of danger signals from necrotic neurons, induce morphological and phenotypic shifts in microglia. This leads them to adopt a proinflammatory profile and heighten their phagocytic activity. From day three post-ischemia, macrophages infiltrate the necrotic core while microglia amass at the periphery. Further, inflammation prompts a metabolic shift favoring glycolysis, the pentose-phosphate shunt, and lipid synthesis. These shifts, combined with phagocytic lipid intake, drive lipid droplet biogenesis, fuel anabolism, and enable microglia proliferation. Proliferating microglia release trophic factors contributing to protection and repair. However, some microglia accumulate lipids persistently and transform into dysfunctional and potentially harmful foam cells. Studies also showed microglia that either display impaired apoptotic cell clearance, or eliminate synapses, viable neurons, or endothelial cells. Yet, it will be essential to elucidate the viability of engulfed cells, the features of the local environment, the extent of tissue damage, and the temporal sequence. Ischemia provides a rich variety of region- and injury-dependent stimuli for microglia, evolving with time and generating distinct microglia phenotypes including those exhibiting proinflammatory or dysfunctional traits and others showing pro-repair features. Accurate profiling of microglia phenotypes, alongside with a more precise understanding of the associated post-ischemic tissue conditions, is a necessary step to serve as the potential foundation for focused interventions in human stroke.
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Affiliation(s)
- Anna M Planas
- Cerebrovascular Research Laboratory, Department of Neuroscience and Experimental Therapeutics, Instituto de Investigaciones Biomédicas de Barcelona (IIBB), Consejo Superior de Investigaciones Científicas (CSIC), Barcelona, Spain
- Cerebrovascular Diseases, Area of Clinical and Experimental Neuroscience, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS)-Hospital Clínic, Barcelona, Spain
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2
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Tang Y, Wu X, Li J, Li Y, Xu X, Li G, Zhang P, Qin C, Wu LJ, Tang Z, Tian DS. The Emerging Role of Microglial Hv1 as a Target for Immunomodulation in Myelin Repair. Aging Dis 2024; 15:1176-1203. [PMID: 38029392 PMCID: PMC11081154 DOI: 10.14336/ad.2023.1107] [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: 08/17/2023] [Accepted: 11/07/2023] [Indexed: 12/01/2023] Open
Abstract
In the central nervous system (CNS), the myelin sheath ensures efficient interconnection between neurons and contributes to the regulation of the proper function of neuronal networks. The maintenance of myelin and the well-organized subtle process of myelin plasticity requires cooperation among myelin-forming cells, glial cells, and neural networks. The process of cooperation is fragile, and the balance is highly susceptible to disruption by microenvironment influences. Reactive microglia play a critical and complicated role in the demyelination and remyelination process. Recent studies have shown that the voltage-gated proton channel Hv1 is selectively expressed in microglia in CNS, which regulates intracellular pH and is involved in the production of reactive oxygen species, underlying multifaceted roles in maintaining microglia function. This paper begins by examining the molecular mechanisms of demyelination and emphasizes the crucial role of the microenvironment in demyelination. It focuses specifically on the role of Hv1 in myelin repair and its therapeutic potential in CNS demyelinating diseases.
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Affiliation(s)
- Yingxin Tang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Xuan Wu
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Jiarui Li
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Yuanwei Li
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Xiaoxiao Xu
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Gaigai Li
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Ping Zhang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Chuan Qin
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
| | - Zhouping Tang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Dai-Shi Tian
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
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3
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Rifat A, Ossola B, Bürli RW, Dawson LA, Brice NL, Rowland A, Lizio M, Xu X, Page K, Fidzinski P, Onken J, Holtkamp M, Heppner FL, Geiger JRP, Madry C. Differential contribution of THIK-1 K + channels and P2X7 receptors to ATP-mediated neuroinflammation by human microglia. J Neuroinflammation 2024; 21:58. [PMID: 38409076 PMCID: PMC10895799 DOI: 10.1186/s12974-024-03042-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 02/12/2024] [Indexed: 02/28/2024] Open
Abstract
Neuroinflammation is highly influenced by microglia, particularly through activation of the NLRP3 inflammasome and subsequent release of IL-1β. Extracellular ATP is a strong activator of NLRP3 by inducing K+ efflux as a key signaling event, suggesting that K+-permeable ion channels could have high therapeutic potential. In microglia, these include ATP-gated THIK-1 K+ channels and P2X7 receptors, but their interactions and potential therapeutic role in the human brain are unknown. Using a novel specific inhibitor of THIK-1 in combination with patch-clamp electrophysiology in slices of human neocortex, we found that THIK-1 generated the main tonic K+ conductance in microglia that sets the resting membrane potential. Extracellular ATP stimulated K+ efflux in a concentration-dependent manner only via P2X7 and metabotropic potentiation of THIK-1. We further demonstrated that activation of P2X7 was mandatory for ATP-evoked IL-1β release, which was strongly suppressed by blocking THIK-1. Surprisingly, THIK-1 contributed only marginally to the total K+ conductance in the presence of ATP, which was dominated by P2X7. This suggests a previously unknown, K+-independent mechanism of THIK-1 for NLRP3 activation. Nuclear sequencing revealed almost selective expression of THIK-1 in human brain microglia, while P2X7 had a much broader expression. Thus, inhibition of THIK-1 could be an effective and, in contrast to P2X7, microglia-specific therapeutic strategy to contain neuroinflammation.
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Affiliation(s)
- Ali Rifat
- Institute of Neurophysiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
- Berlin Institute of Health at Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Bernardino Ossola
- Cerevance Ltd, 418 Cambridge Science Park, Milton Road, Cambridge, CB4 0PZ, UK
| | - Roland W Bürli
- Cerevance Ltd, 418 Cambridge Science Park, Milton Road, Cambridge, CB4 0PZ, UK
| | - Lee A Dawson
- Cerevance Ltd, 418 Cambridge Science Park, Milton Road, Cambridge, CB4 0PZ, UK
| | - Nicola L Brice
- Cerevance Ltd, 418 Cambridge Science Park, Milton Road, Cambridge, CB4 0PZ, UK
| | - Anna Rowland
- Cerevance Ltd, 418 Cambridge Science Park, Milton Road, Cambridge, CB4 0PZ, UK
| | - Marina Lizio
- Cerevance Ltd, 418 Cambridge Science Park, Milton Road, Cambridge, CB4 0PZ, UK
| | - Xiao Xu
- Cerevance Ltd, 418 Cambridge Science Park, Milton Road, Cambridge, CB4 0PZ, UK
| | - Keith Page
- Cerevance Ltd, 418 Cambridge Science Park, Milton Road, Cambridge, CB4 0PZ, UK
| | - Pawel Fidzinski
- Berlin Institute of Health at Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
- Department of Neurology, Epilepsy-Center Berlin-Brandenburg, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
- Neurocure Cluster of Excellence, Neuroscience Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Julia Onken
- Berlin Institute of Health at Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
- Department of Neurosurgery, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Martin Holtkamp
- Department of Neurology, Epilepsy-Center Berlin-Brandenburg, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Frank L Heppner
- Neurocure Cluster of Excellence, Neuroscience Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
- Department of Neuropathology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
- German Center for Neurodegenerative Diseases (DZNE) Berlin, 10117, Berlin, Germany
| | - Jörg R P Geiger
- Institute of Neurophysiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Christian Madry
- Institute of Neurophysiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany.
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Tewari M, Michalski S, Egan TM. Modulation of Microglial Function by ATP-Gated P2X7 Receptors: Studies in Rat, Mice and Human. Cells 2024; 13:161. [PMID: 38247852 PMCID: PMC10814008 DOI: 10.3390/cells13020161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 01/10/2024] [Accepted: 01/12/2024] [Indexed: 01/23/2024] Open
Abstract
P2X receptors are a family of seven ATP-gated ion channels that trigger physiological and pathophysiological responses in a variety of cells. Five of the family members are sensitive to low concentrations of extracellular ATP, while the P2X6 receptor has an unknown affinity. The last subtype, the P2X7 receptor, is unique in requiring millimolar concentrations to fully activate in humans. This low sensitivity imparts the agonist with the ability to act as a damage-associated molecular pattern that triggers the innate immune response in response to the elevated levels of extracellular ATP that accompany inflammation and tissue damage. In this review, we focus on microglia because they are the primary immune cells of the central nervous system, and they activate in response to ATP or its synthetic analog, BzATP. We start by introducing purinergic receptors and then briefly consider the roles that microglia play in neurodevelopment and disease by referencing both original works and relevant reviews. Next, we move to the role of extracellular ATP and P2X receptors in initiating and/or modulating innate immunity in the central nervous system. While most of the data that we review involve work on mice and rats, we highlight human studies of P2X7R whenever possible.
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Gheorghe RO, Grosu AV, Magercu M, Ghenghea MS, Zbarcea CE, Tanase A, Negres S, Filippi A, Chiritoiu G, Gherghiceanu M, Dinescu S, Gaina G, Sapunar D, Ristoiu V. Switching Rat Resident Macrophages from M1 to M2 Phenotype by Iba1 Silencing Has Analgesic Effects in SNL-Induced Neuropathic Pain. Int J Mol Sci 2023; 24:15831. [PMID: 37958812 PMCID: PMC10648812 DOI: 10.3390/ijms242115831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/16/2023] [Accepted: 10/20/2023] [Indexed: 11/15/2023] Open
Abstract
Resident macrophages from dorsal root ganglia are important for the development of traumatic-induced neuropathic pain. In the first 5-7 days after a traumatic sciatic nerve injury (i.e., spinal nerve ligation (SNL), spared nerve injury (SNI), sciatic nerve transection or sciatic nerve ligation and transection), Ionized binding adapter protein 1 (Iba1) (+) resident macrophages cluster around dorsal root ganglia neurons, possibly contributing to nerve injury-induced hypersensitivity. Since infiltrating macrophages gradually recruited to the lesion site peak at about 7 days, the first few days post-lesion offer a window of opportunity when the contribution of Iba1 (+) resident macrophages to neuropathic pain pathogenesis could be investigated. Iba1 is an actin cross-linking cytoskeleton protein, specifically located only in macrophages and microglia. In this study, we explored the contribution of rat Iba1 (+) macrophages in SNL-induced neuropathic pain by using intra-ganglionic injections of naked Iba1-siRNA, delivered at the time the lesion occurred. The results show that 5 days after Iba1 silencing, Iba1 (+) resident macrophages are switched from an M1 (pro-inflammatory) phenotype to an M2 (anti-inflammatory) phenotype, which was confirmed by a significant decrease of M1 markers (CD32 and CD86), a significant increase of M2 markers (CD163 and Arginase-1), a reduced secretion of pro-inflammatory cytokines (IL-6, TNF-α and IL-1β) and an increased release of pro-regenerative factors (BDNF, NGF and NT-3) which initiated the regrowth of adult DRG neurites and reduced SNL-induced neuropathic pain. Our data show for the first time, that it is possible to induce macrophages towards an anti-inflammatory phenotype by interacting with their cytoskeleton.
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Affiliation(s)
- Roxana-Olimpia Gheorghe
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, District 5, 050095 Bucharest, Romania; (R.-O.G.)
| | - Andreea Violeta Grosu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, District 5, 050095 Bucharest, Romania; (R.-O.G.)
| | - Melania Magercu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, District 5, 050095 Bucharest, Romania; (R.-O.G.)
| | - Mihail-Sebastian Ghenghea
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, District 5, 050095 Bucharest, Romania; (R.-O.G.)
| | - Cristina Elena Zbarcea
- Department of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, University of Medicine and Pharmacy “Carol Davila”, 6 Traian Vuia Street, District 2, 02095 Bucharest, Romania
| | - Alexandra Tanase
- Department of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, University of Medicine and Pharmacy “Carol Davila”, 6 Traian Vuia Street, District 2, 02095 Bucharest, Romania
| | - Simona Negres
- Department of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, University of Medicine and Pharmacy “Carol Davila”, 6 Traian Vuia Street, District 2, 02095 Bucharest, Romania
| | - Alexandru Filippi
- Department of Biophysics, University of Medicine and Pharmacy “Carol Davila”, 8 Eroilor Sanitari Blvd., 050474 Bucharest, Romania
| | - Gabriela Chiritoiu
- Department of Molecular Cell Biology, Institute of Biochemistry, Romanian Academy, 2996 Splaiul Independentei 296, District 6, 060031 Bucharest, Romania
| | - Mihaela Gherghiceanu
- Ultrastructural Pathology and Bioimaging Laboratory, Victor Babeș National Institute of Pathology Bucharest, 99-101 Splaiul Independentei, District 5, 050096 Bucharest, Romania
| | - Sorina Dinescu
- Department of Biochemistry and Molecular Biology, University of Bucharest, 91-95 Splaiul Independentei, District 5, 050095 Bucharest, Romania
| | - Gisela Gaina
- Department of Biochemistry and Molecular Biology, University of Bucharest, 91-95 Splaiul Independentei, District 5, 050095 Bucharest, Romania
| | - Damir Sapunar
- Department of Anatomy, Histology and Embryology, University of Split School of Medicine, Šoltanska 2, 21000 Split, Croatia
| | - Violeta Ristoiu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, District 5, 050095 Bucharest, Romania; (R.-O.G.)
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6
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Seki E, Komori T, Arai N. Expanded ischemic lesion due to herniation leads to axonal injury in a site remote to the primary lesion on autopsy brain with acute focal cerebral ischemia. Neuropathology 2023; 43:373-384. [PMID: 36855231 DOI: 10.1111/neup.12900] [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: 01/10/2023] [Revised: 02/05/2023] [Accepted: 02/11/2023] [Indexed: 03/02/2023]
Abstract
Cerebral ischemia may lead to axonal injury not only at the site of the primary lesion but also in a region remote to the site of insult. In this study, we investigated the effect of herniation on the development of axonal injury at a site remote to the primary lesion during the acute phase of cerebral ischemia. We obtained postmortem brains of 13 cases with acute phase of unilateral cerebral infarction in the territory of the internal carotid artery or middle cerebral artery and seven controls. We classified the brain tissues into herniation and non-herniation groups. Then we examined whether axonal and ischemic changes existed in the corpus callosum contralateral to the ischemic hemisphere and the upper pons. In the herniation group, we detected white-matter lesions by Klüver-Barrera staining, microglial loss by immunohistochemistry for ionized calcium-binding adaptor molecule 1, and axonal injury by immunohistochemistry for amyloid precursor protein. However, none of the aforementioned findings were observed in the non-herniation group. These findings suggest the existence of regional overlap in axonal and ischemic pathologies in remote regions in the presence of herniation. We concluded that herniation may play a significant role in the development of axonal and ischemic changes in the remote region. Our results suggest that axonal injury in a remote region may result from expanded ischemic lesions due to herniation.
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Affiliation(s)
- Erika Seki
- Laboratory of Neuropathology, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Japan
| | - Takashi Komori
- Department of Laboratory Medicine and Pathology (Neuropathology), Tokyo Metropolitan Neurological Hospital, Tokyo Metropolitan Hospital Organization, Fuchu, Japan
| | - Nobutaka Arai
- Laboratory of Neuropathology, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Japan
- Department of Laboratory Medicine and Pathology (Neuropathology), Tokyo Metropolitan Neurological Hospital, Tokyo Metropolitan Hospital Organization, Fuchu, Japan
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7
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Yin Y, Wei L, Caseley EA, Lopez‐Charcas O, Wei Y, Li D, Muench SP, Roger S, Wang L, Jiang L. Leveraging the ATP-P2X7 receptor signalling axis to alleviate traumatic CNS damage and related complications. Med Res Rev 2023; 43:1346-1373. [PMID: 36924449 PMCID: PMC10947395 DOI: 10.1002/med.21952] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 11/11/2022] [Accepted: 02/28/2023] [Indexed: 03/18/2023]
Abstract
The P2X7 receptor is an exceptional member of the P2X purinergic receptor family, with its activation requiring high concentrations of extracellular adenosine 5'-triphosphate (ATP) that are often associated with tissue damage and inflammation. In the central nervous system (CNS), it is highly expressed in glial cells, particularly in microglia. In this review, we discuss the role and mechanisms of the P2X7 receptor in mediating neuroinflammation and other pathogenic events in a variety of traumatic CNS damage conditions, which lead to loss of neurological and cognitive functions. We raise the perspective on the steady progress in developing CNS-penetrant P2X7 receptor-specific antagonists that leverage the ATP-P2X7 receptor signaling axis as a potential therapeutic strategy to alleviate traumatic CNS damage and related complications.
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Affiliation(s)
- Yaling Yin
- Sino‐UK Joint Laboratory of Brain Function and Injury of Henan Province, Department of Physiology and PathophysiologyXinxiang Medical UniversityXinxiangChina
| | - Linyu Wei
- Sino‐UK Joint Laboratory of Brain Function and Injury of Henan Province, Department of Physiology and PathophysiologyXinxiang Medical UniversityXinxiangChina
| | - Emily A. Caseley
- Faculty of Biological Sciences, School of Biomedical SciencesUniversity of LeedsLeedsUK
| | - Osbaldo Lopez‐Charcas
- EA4245, Transplantation, Immunology and Inflammation, Faculty of MedicineUniversity of ToursToursFrance
| | - Yingjuan Wei
- Sino‐UK Joint Laboratory of Brain Function and Injury of Henan Province, Department of Physiology and PathophysiologyXinxiang Medical UniversityXinxiangChina
| | - Dongliang Li
- Sino‐UK Joint Laboratory of Brain Function and Injury of Henan Province, Department of Physiology and PathophysiologyXinxiang Medical UniversityXinxiangChina
- Sanquan College of Xinxiang Medical UniversityXinxiangChina
| | - Steve P. Muench
- Faculty of Biological Sciences, School of Biomedical SciencesUniversity of LeedsLeedsUK
| | - Sebastian Roger
- EA4245, Transplantation, Immunology and Inflammation, Faculty of MedicineUniversity of ToursToursFrance
| | - Lu Wang
- Sino‐UK Joint Laboratory of Brain Function and Injury of Henan Province, Department of Physiology and PathophysiologyXinxiang Medical UniversityXinxiangChina
| | - Lin‐Hua Jiang
- Sino‐UK Joint Laboratory of Brain Function and Injury of Henan Province, Department of Physiology and PathophysiologyXinxiang Medical UniversityXinxiangChina
- Faculty of Biological Sciences, School of Biomedical SciencesUniversity of LeedsLeedsUK
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8
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Huang Y, Omorou M, Gao M, Mu C, Xu W, Xu H. Hydrogen sulfide and its donors for the treatment of cerebral ischaemia-reperfusion injury: A comprehensive review. Biomed Pharmacother 2023; 161:114506. [PMID: 36906977 DOI: 10.1016/j.biopha.2023.114506] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/06/2023] [Accepted: 03/07/2023] [Indexed: 03/12/2023] Open
Abstract
As an endogenous gas signalling molecule, hydrogen sulfide (H2S) is frequently present in a variety of mammals and plays a significant role in the cardiovascular and nervous systems. Reactive oxygen species (ROS) are produced in large quantities as a result of cerebral ischaemia-reperfusion, which is a very serious class of cerebrovascular diseases. ROS cause oxidative stress and induce specific gene expression that results in apoptosis. H2S reduces cerebral ischaemia-reperfusion-induced secondary injury via anti-oxidative stress injury, suppression of the inflammatory response, inhibition of apoptosis, attenuation of cerebrovascular endothelial cell injury, modulation of autophagy, and antagonism of P2X7 receptors, and it plays an important biological role in other cerebral ischaemic injury events. Despite the many limitations of the hydrogen sulfide therapy delivery strategy and the difficulty in controlling the ideal concentration, relevant experimental evidence demonstrating that H2S plays an excellent neuroprotective role in cerebral ischaemia-reperfusion injury (CIRI). This paper examines the synthesis and metabolism of the gas molecule H2S in the brain as well as the molecular mechanisms of H2S donors in cerebral ischaemia-reperfusion injury and possibly other unknown biological functions. With the active development in this field, it is expected that this review will assist researchers in their search for the potential value of hydrogen sulfide and provide new ideas for preclinical trials of exogenous H2S.
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Affiliation(s)
- Yiwei Huang
- Basic Medical College, Jiamusi University, Jiamusi 154007, Heilongjiang, China; Key Laboratory of Microecology-Immune Regulatory Network and Related Diseases, Jiamusi 154007, Heilongjiang, China.
| | - Moussa Omorou
- Key Laboratory of Microecology-Immune Regulatory Network and Related Diseases, Jiamusi 154007, Heilongjiang, China; Basic Medical College, Jiamusi University, Jiamusi 154007, Heilongjiang, China.
| | - Meng Gao
- Key Laboratory of Microecology-Immune Regulatory Network and Related Diseases, Jiamusi 154007, Heilongjiang, China; Basic Medical College, Jiamusi University, Jiamusi 154007, Heilongjiang, China.
| | - Chenxi Mu
- Key Laboratory of Microecology-Immune Regulatory Network and Related Diseases, Jiamusi 154007, Heilongjiang, China; Basic Medical College, Jiamusi University, Jiamusi 154007, Heilongjiang, China.
| | - Weijing Xu
- School of Public Health, Jiamusi University, Jiamusi 154007, Heilongjiang, China.
| | - Hui Xu
- Key Laboratory of Microecology-Immune Regulatory Network and Related Diseases, Jiamusi 154007, Heilongjiang, China.
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9
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Gu N, Yi MH, Murugan M, Xie M, Parusel S, Peng J, Eyo UB, Hunt CL, Dong H, Wu LJ. Spinal microglia contribute to sustained inflammatory pain via amplifying neuronal activity. Mol Brain 2022; 15:86. [PMID: 36289499 PMCID: PMC9609165 DOI: 10.1186/s13041-022-00970-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 10/10/2022] [Indexed: 01/05/2023] Open
Abstract
Microglia are highly dynamic immune cells of the central nervous system (CNS). Microglial processes interact with neuronal elements constantly on the order of minutes. The functional significance of this acute microglia-neuron interaction and its potential role in the context of pain is still largely unknown. Here, we found that spinal microglia increased their process motility and electrophysiological reactivity within an hour after the insult in a mouse model of formalin-induced acute, sustained, inflammatory pain. Using an ablation strategy to specifically deplete resident microglia in the CNS, we demonstrate that microglia participate in formalin-induced acute sustained pain behaviors by amplifying neuronal activity in the spinal dorsal horn. Moreover, we identified that the P2Y12 receptor, which is specifically expressed in microglia in the CNS, was required for microglial function in formalin-induced pain. Taken together, our study provides a novel insight into the contribution of microglia and the P2Y12 receptor in inflammatory pain that could be used for potential therapeutic strategies.
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Affiliation(s)
- Nan Gu
- grid.430387.b0000 0004 1936 8796Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854 USA ,grid.417295.c0000 0004 1799 374XDepartment of Anesthesiology & Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi 710032 PR China
| | - Min-Hee Yi
- grid.66875.3a0000 0004 0459 167XDepartment of Neurology, Mayo Clinic, Rochester, MN 55905 USA
| | - Madhuvika Murugan
- grid.430387.b0000 0004 1936 8796Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854 USA ,grid.66875.3a0000 0004 0459 167XDepartment of Neurology, Mayo Clinic, Rochester, MN 55905 USA
| | - Manling Xie
- grid.66875.3a0000 0004 0459 167XDepartment of Neurology, Mayo Clinic, Rochester, MN 55905 USA
| | - Sebastian Parusel
- grid.66875.3a0000 0004 0459 167XDepartment of Neurology, Mayo Clinic, Rochester, MN 55905 USA
| | - Jiyun Peng
- grid.430387.b0000 0004 1936 8796Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854 USA ,grid.66875.3a0000 0004 0459 167XDepartment of Neurology, Mayo Clinic, Rochester, MN 55905 USA
| | - Ukpong B. Eyo
- grid.430387.b0000 0004 1936 8796Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854 USA ,grid.66875.3a0000 0004 0459 167XDepartment of Neurology, Mayo Clinic, Rochester, MN 55905 USA
| | - Christine L. Hunt
- grid.417467.70000 0004 0443 9942Department of Pain Medicine, Mayo Clinic, Jacksonville, FL 32224 USA
| | - Hailong Dong
- grid.417295.c0000 0004 1799 374XDepartment of Anesthesiology & Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi 710032 PR China
| | - Long-Jun Wu
- grid.430387.b0000 0004 1936 8796Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854 USA ,grid.66875.3a0000 0004 0459 167XDepartment of Neurology, Mayo Clinic, Rochester, MN 55905 USA ,grid.417467.70000 0004 0443 9942Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224 USA ,grid.66875.3a0000 0004 0459 167XDepartment of Immunology, Mayo Clinic, Rochester, MN 55905 USA
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Blocking P2X7 by intracerebroventricular injection of P2X7-specific nanobodies reduces stroke lesions. J Neuroinflammation 2022; 19:256. [PMID: 36224611 PMCID: PMC9559872 DOI: 10.1186/s12974-022-02601-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 09/25/2022] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Previous studies have demonstrated that purinergic receptors could be therapeutic targets to modulate the inflammatory response in multiple models of brain diseases. However, tools for the selective and efficient targeting of these receptors are lacking. The development of new P2X7-specific nanobodies (nbs) has enabled us to effectively block the P2X7 channel. METHODS Temporary middle cerebral artery occlusion (tMCAO) in wild-type (wt) and P2X7 transgenic (tg) mice was used to model ischemic stroke. Adenosine triphosphate (ATP) release was assessed in transgenic ATP sensor mice. Stroke size was measured after P2X7-specific nbs were injected intravenously (iv) and intracerebroventricularly (icv) directly before tMCAO surgery. In vitro cultured microglia were used to investigate calcium influx, pore formation via 4,6-diamidino-2-phenylindole (DAPI) uptake, caspase 1 activation and interleukin (IL)-1β release after incubation with the P2X7-specific nbs. RESULTS Transgenic ATP sensor mice showed an increase in ATP release in the ischemic hemisphere compared to the contralateral hemisphere or the sham-treated mice up to 24 h after stroke. P2X7-overexpressing mice had a significantly greater stroke size 24 h after tMCAO surgery. In vitro experiments with primary microglial cells demonstrated that P2X7-specific nbs could inhibit ATP-triggered calcium influx and the formation of membrane pores, as measured by Fluo4 fluorescence or DAPI uptake. In microglia, we found lower caspase 1 activity and subsequently lower IL-1β release after P2X7-specific nb treatment. The intravenous injection of P2X7-specific nbs compared to isotype controls before tMCAO surgery did not result in a smaller stroke size. As demonstrated by fluorescence-activated cell sorting (FACS), after stroke, iv injected nbs bound to brain-infiltrated macrophages but not to brain resident microglia, indicating insufficient crossing of the blood-brain barrier of the nbs. Therefore, we directly icv injected the P2X7-specific nbs or the isotype nbs. After icv injection of 30 µg of P2X7 specific nbs, P2X7 specific nbs bound sufficiently to microglia and reduced stroke size. CONCLUSION Mechanistically, we can show that there is a substantial increase of ATP locally after stroke and that blockage of the ATP receptor P2X7 by icv injected P2X7-specific nbs can reduce ischemic tissue damage.
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11
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Microglia Phenotypes in Aging and Neurodegenerative Diseases. Cells 2022; 11:cells11132091. [PMID: 35805174 PMCID: PMC9266143 DOI: 10.3390/cells11132091] [Citation(s) in RCA: 77] [Impact Index Per Article: 38.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 06/24/2022] [Accepted: 06/29/2022] [Indexed: 02/08/2023] Open
Abstract
Neuroinflammation is a hallmark of many neurodegenerative diseases (NDs) and plays a fundamental role in mediating the onset and progression of disease. Microglia, which function as first-line immune guardians of the central nervous system (CNS), are the central drivers of neuroinflammation. Numerous human postmortem studies and in vivo imaging analyses have shown chronically activated microglia in patients with various acute and chronic neuropathological diseases. While microglial activation is a common feature of many NDs, the exact role of microglia in various pathological states is complex and often contradictory. However, there is a consensus that microglia play a biphasic role in pathological conditions, with detrimental and protective phenotypes, and the overall response of microglia and the activation of different phenotypes depends on the nature and duration of the inflammatory insult, as well as the stage of disease development. This review provides a comprehensive overview of current research on the various microglia phenotypes and inflammatory responses in health, aging, and NDs, with a special emphasis on the heterogeneous phenotypic response of microglia in acute and chronic diseases such as hemorrhagic stroke (HS), Alzheimer’s disease (AD), and Parkinson’s disease (PD). The primary focus is translational research in preclinical animal models and bulk/single-cell transcriptome studies in human postmortem samples. Additionally, this review covers key microglial receptors and signaling pathways that are potential therapeutic targets to regulate microglial inflammatory responses during aging and in NDs. Additionally, age-, sex-, and species-specific microglial differences will be briefly reviewed.
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12
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Matyśniak D, Chumak V, Nowak N, Kukla A, Lehka L, Oslislok M, Pomorski P. P2X7 receptor: the regulator of glioma tumor development and survival. Purinergic Signal 2021; 18:135-154. [PMID: 34964926 PMCID: PMC8850512 DOI: 10.1007/s11302-021-09834-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 12/05/2021] [Indexed: 11/26/2022] Open
Abstract
P2X7 is an ionotropic nucleotide receptor, forming the cation channel upon ATP stimulation. It can also function as a large membrane pore as well as transmit ATP-dependent signal without forming a channel at all. P2X7 activity in somatic cells is well-known, but remains poorly studied in glioma tumors. The current paper presents the comprehensive study of P2X7 activity in C6 and glioma cell line showing the wide range of effects the receptor has on glioma biology. We observed that P2X7 stimulation boosts glioma cell proliferation and increases cell viability. P2X7 activation promoted cell adhesion, mitochondria depolarization, and reactive oxygen species overproduction in C6 cells. P2X7 receptor also influenced glioma tumor growth in vivo via activation of pro-survival signaling pathways and ATP release. Treatment with Brilliant Blue G, a selective P2X7 antagonist, effectively inhibited glioma tumor development; decreased the expression of negative prognostic cancer markers pro-survival and epithelial-mesenchymal transition (EMT)-related proteins; and modulated the immune response toward glioma tumor in vivo. Finally, pathway-specific enrichment analysis of the microarray data from human patients also showed an upregulation of P2X7 receptor in gliomas from grades I to III. The presented results shed more light on the role of P2X7 receptor in the biology of this disease.
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Affiliation(s)
- Damian Matyśniak
- Laboratory of Molecular Basis of Cell Motility, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Str., 02-093, Warsaw, Poland
| | - Vira Chumak
- Laboratory of Molecular Basis of Cell Motility, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Str., 02-093, Warsaw, Poland
- Regenerative Medicine Department, Medical University of Warsaw, Warsaw, Poland
| | - Natalia Nowak
- Laboratory of Imaging Tissue Structure and Function, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Artur Kukla
- Silesian University of Technology, Gliwice, Poland
| | - Lilya Lehka
- Institute of Cell Biology, National Academy of Sciences of Ukraine, Lviv, Ukraine
| | - Magdalena Oslislok
- Department of Embryology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Paweł Pomorski
- Laboratory of Molecular Basis of Cell Motility, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Str., 02-093, Warsaw, Poland.
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13
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Mertens N, Schmidt ME, Hijzen A, Van Weehaeghe D, Ravenstijn P, Depre M, de Hoon J, Van Laere K, Koole M. Minimally invasive quantification of cerebral P2X7R occupancy using dynamic [ 18F]JNJ-64413739 PET and MRA-driven image derived input function. Sci Rep 2021; 11:16172. [PMID: 34373571 PMCID: PMC8352986 DOI: 10.1038/s41598-021-95715-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Accepted: 07/29/2021] [Indexed: 01/21/2023] Open
Abstract
[18F]JNJ-64413739 has been evaluated as PET-ligand for in vivo quantification of purinergic receptor subtype 7 receptor (P2X7R) using Logan graphical analysis with a metabolite-corrected arterial plasma input function. In the context of a P2X7R PET dose occupancy study, we evaluated a minimally invasive approach by limiting arterial sampling to baseline conditions. Meanwhile, post dose distribution volumes (VT) under blocking conditions were estimated by combining baseline blood to plasma ratios and metabolite fractions with an MR angiography driven image derived input function (IDIF). Regional postdose VT,IDIF values were compared with corresponding VT,AIF estimates using a arterial input function (AIF), in terms of absolute values, test–retest reliability and receptor occupancy. Compared to an invasive AIF approach, postdose VT,IDIF values and corresponding receptor occupancies showed only limited bias (Bland–Altman analysis: 0.06 ± 0.27 and 3.1% ± 6.4%) while demonstrating a high correlation (Spearman ρ = 0.78 and ρ = 0.98 respectively). In terms of test–retest reliability, regional intraclass correlation coefficients were 0.98 ± 0.02 for VT,IDIF compared to 0.97 ± 0.01 for VT,AIF. These results confirmed that a postdose IDIF, guided by MR angiography and using baseline blood and metabolite data, can be considered for accurate [18F]JNJ-64413739 PET quantification in a repeated PET study design, thus avoiding multiple invasive arterial sampling and increasing dosing flexibility.
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Affiliation(s)
- Nathalie Mertens
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, University Hospital and KU Leuven, Herestraat 49, 3000, Leuven, Belgium.
| | | | - Anja Hijzen
- Janssen Research and Development, Beerse, Belgium
| | - Donatienne Van Weehaeghe
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, University Hospital and KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | | | - Marleen Depre
- Center for Clinical Pharmacology, University Hospital and KU Leuven, Leuven, Belgium
| | - Jan de Hoon
- Center for Clinical Pharmacology, University Hospital and KU Leuven, Leuven, Belgium
| | - Koen Van Laere
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, University Hospital and KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Michel Koole
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, University Hospital and KU Leuven, Herestraat 49, 3000, Leuven, Belgium
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14
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Huang Z, Tan S. P2X7 Receptor as a Potential Target for Major Depressive Disorder. Curr Drug Targets 2021; 22:1108-1120. [PMID: 33494675 DOI: 10.2174/1389450122666210120141908] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 11/04/2020] [Accepted: 11/06/2020] [Indexed: 11/22/2022]
Abstract
Major depressive disorder (MDD) is a common mental disorder. Although the genetic, biochemical, and psychological factors have been related to the development of MDD, it is generally believed that a series of pathological changes in the brain caused by chronic stress is the main cause of MDD. However, the specific mechanisms underlying chronic stress-induced MDD are largely undermined. Recent investigations have found that increased pro-inflammatory cytokines and changes in the inflammatory pathway in the microglia cells in the brain are the potential pathophysiological mechanism of MDD. P2X7 receptor (P2X7R) and its mediated signaling pathway play a key role in microglia activation. The present review aimed to present and discuss the accumulating data on the role of P2X7R in MDD. Firstly, we summarized the research progress in the correlation between P2X7R and MDD. Subsequently, we presented the P2X7R mediated microglia activation in MDD and the role of P2X7R in increased blood-brain barrier (BBB) permeability caused by chronic stress. Lastly, we also discussed the potential mechanism underlying-P2X7R expression changes after chronic stress. In conclusion, P2X7R is a key molecule regulating the activation of microglia. Chronic stress activates microglia in the hippocampus by secreting interleukin- 1β (IL-1β) and other inflammatory cytokines, and increasing the BBB permeability, thus promoting the occurrence and development of MDD, which indicated that P2X7R might be a promising therapeutic target for MDD.
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Affiliation(s)
- Zeyi Huang
- Department of Histology and Embryology, Institute of Clinical Anatomy & Reproductive Medicine, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical College, University of South China, 421001, Hunan, China
| | - Sijie Tan
- Department of Histology and Embryology, Institute of Clinical Anatomy & Reproductive Medicine, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical College, University of South China, 421001, Hunan, China
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15
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Zhang S, Lachance BB, Mattson MP, Jia X. Glucose metabolic crosstalk and regulation in brain function and diseases. Prog Neurobiol 2021; 204:102089. [PMID: 34118354 DOI: 10.1016/j.pneurobio.2021.102089] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 04/08/2021] [Accepted: 06/01/2021] [Indexed: 01/11/2023]
Abstract
Brain glucose metabolism, including glycolysis, the pentose phosphate pathway, and glycogen turnover, produces ATP for energetic support and provides the precursors for the synthesis of biological macromolecules. Although glucose metabolism in neurons and astrocytes has been extensively studied, the glucose metabolism of microglia and oligodendrocytes, and their interactions with neurons and astrocytes, remain critical to understand brain function. Brain regions with heterogeneous cell composition and cell-type-specific profiles of glucose metabolism suggest that metabolic networks within the brain are complex. Signal transduction proteins including those in the Wnt, GSK-3β, PI3K-AKT, and AMPK pathways are involved in regulating these networks. Additionally, glycolytic enzymes and metabolites, such as hexokinase 2, acetyl-CoA, and enolase 2, are implicated in the modulation of cellular function, microglial activation, glycation, and acetylation of biomolecules. Given these extensive networks, glucose metabolism dysfunction in the whole brain or specific cell types is strongly associated with neurologic pathology including ischemic brain injury and neurodegenerative disorders. This review characterizes the glucose metabolism networks of the brain based on molecular signaling and cellular and regional interactions, and elucidates glucose metabolism-based mechanisms of neurological diseases and therapeutic approaches that may ameliorate metabolic abnormalities in those diseases.
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Affiliation(s)
- Shuai Zhang
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, 21201, United States
| | - Brittany Bolduc Lachance
- Program in Trauma, Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, 21201, United States
| | - Mark P Mattson
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, United States
| | - Xiaofeng Jia
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, 21201, United States; Department of Orthopedics, University of Maryland School of Medicine, Baltimore, MD, 21201, United States; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, United States; Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, United States; Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, United States.
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16
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Territo PR, Zarrinmayeh H. P2X 7 Receptors in Neurodegeneration: Potential Therapeutic Applications From Basic to Clinical Approaches. Front Cell Neurosci 2021; 15:617036. [PMID: 33889073 PMCID: PMC8055960 DOI: 10.3389/fncel.2021.617036] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 03/02/2021] [Indexed: 12/27/2022] Open
Abstract
Purinergic receptors play important roles in central nervous system (CNS), where the bulk of these receptors are implicated in neuroinflammatory responses and regulation of cellular function of neurons, microglial and astrocytes. Within the P2X receptor family, P2X7 receptor is generally known for its inactivity in normal conditions and activation by moderately high concentrations (>100 μM) of extracellular adenosine 5′-triphosphate (ATP) released from injured cells as a result of brain injury or pathological conditions. Activation of P2X7R contributes to the activation and proliferation of microglia and directly contribute to neurodegeneration by provoking microglia-mediated neuronal death, glutamate-mediated excitotoxicity, and NLRP3 inflammasome activation that results in initiation, maturity and release of the pro-inflammatory cytokines and generation of reactive oxygen and nitrogen species. These components of the inflammatory response play important roles in many neural pathologies and neurodegeneration disorders. In CNS, expression of P2X7R on microglia, astrocytes, and oligodendrocytes are upregulated under neuroinflammatory conditions. Several in vivo studies have demonstrated beneficial effects of the P2X7 receptor antagonists in animal model systems of neurodegenerative diseases. A number of specific and selective P2X7 receptor antagonists have been developed, but only few of them have shown efficient brain permeability. Finding potent and selective P2X7 receptor inhibitors which are also CNS penetrable and display acceptable pharmacokinetics (PK) has presented challenges for both academic researchers and pharmaceutical companies. In this review, we discuss the role of P2X7 receptor function in neurodegenerative diseases, the pharmacological inhibition of the receptor, and PET radiopharmaceuticals which permit non-invasive monitoring of the P2X7 receptor contribution to neuroinflammation associated with neurodegeneration.
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Affiliation(s)
- Paul R Territo
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, United States.,Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Hamideh Zarrinmayeh
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, United States
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17
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Weitbrecht L, Berchtold D, Zhang T, Jagdmann S, Dames C, Winek K, Meisel C, Meisel A. CD4 + T cells promote delayed B cell responses in the ischemic brain after experimental stroke. Brain Behav Immun 2021; 91:601-614. [PMID: 33002634 DOI: 10.1016/j.bbi.2020.09.029] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 08/13/2020] [Accepted: 09/24/2020] [Indexed: 01/20/2023] Open
Abstract
CD4+ T lymphocytes are key mediators of tissue damage after ischemic stroke. However, their infiltration kinetics and interactions with other immune cells in the delayed phase of ischemia remain elusive. We hypothesized that CD4+ T cells facilitate delayed autoreactive B cell responses in the brain, which have been previously linked to post-stroke cognitive impairment (PSCI). Therefore, we treated myelin oligodendrocyte glycoprotein T cell receptor transgenic 2D2 mice of both sexes with anti-CD4 antibody following 60-minute middle cerebral artery occlusion and assessed lymphocyte infiltration for up to 72 days. Anti-CD4-treatment eliminated CD4+ T cells from the circulation and ischemic brain for 28 days and inhibited B cell infiltration into the brain, particularly in animals with large infarcts. Absence of CD4+ T cells did not influence infarct maturation or survival. Once the CD4+ population recovered in the periphery, both CD4+ T and B lymphocytes entered the infarct site forming follicle-like structures. Additionally, we provide further evidence for PSCI that could be attenuated by CD4 depletion. Our findings demonstrate that CD4+ T cells are essential in delayed B cell infiltration into the ischemic brain after stroke. Importantly, lymphocyte infiltration after stroke is a long-lasting process. As CD4 depletion improved cognitive functions in an experimental set-up, these findings set the stage to elaborate more specific immune modulating therapies in treating PSCI.
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Affiliation(s)
- Luis Weitbrecht
- Charité - Universitätsmedizin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Experimental Neurology, Germany
| | - Daniel Berchtold
- Charité - Universitätsmedizin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Experimental Neurology, Germany
| | - Tian Zhang
- Charité - Universitätsmedizin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Experimental Neurology, Germany
| | - Sandra Jagdmann
- Charité - Universitätsmedizin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute for Medical Immunology, Germany
| | - Claudia Dames
- Charité - Universitätsmedizin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute for Medical Immunology, Germany
| | - Katarzyna Winek
- Charité - Universitätsmedizin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Experimental Neurology, Germany
| | - Christian Meisel
- Charité - Universitätsmedizin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute for Medical Immunology, Germany
| | - Andreas Meisel
- Charité - Universitätsmedizin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Experimental Neurology, Germany; Charité - Universitätsmedizin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Center for Stroke Research Berlin, Germany; Charité - Universitätsmedizin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Neurocure Cluster of Excellence, Germany; Charité - Universitätsmedizin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Neurology, Germany.
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18
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Umpierre AD, Wu LJ. How microglia sense and regulate neuronal activity. Glia 2020; 69:1637-1653. [PMID: 33369790 DOI: 10.1002/glia.23961] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 12/17/2020] [Accepted: 12/18/2020] [Indexed: 12/16/2022]
Abstract
Microglia are innate immune cells of the central nervous system that sense extracellular cues. Brain injuries, inflammation, and pathology evoke dynamic structural responses in microglia, altering their morphology and motility. The dynamic motility of microglia is hypothesized to be a critical first step in sensing local alterations and engaging in pattern-specific responses. Alongside their pathological responses, microglia also sense and regulate neuronal activity. In this review, we consider the extracellular molecules, receptors, and mechanisms that allow microglia to sense neuronal activity changes under both hypoactivity and hyperactivity. We also highlight emerging in vivo evidence that microglia regulate neuronal activity, ranging from physiological to pathophysiological conditions. In addition, we discuss the emerging role of calcium signaling in microglial responses to the extracellular environment. The dynamic function of microglia in monitoring and influencing neuronal activity may be critical for brain homeostasis and circuit modification in health and disease.
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Affiliation(s)
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.,Department of Neuroscience, Mayo Clinic, Jacksonville, Florida, USA.,Department of Immunology, Mayo Clinic, Rochester, Minnesota, USA
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19
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Purinergic signaling orchestrating neuron-glia communication. Pharmacol Res 2020; 162:105253. [PMID: 33080321 DOI: 10.1016/j.phrs.2020.105253] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 09/29/2020] [Accepted: 10/09/2020] [Indexed: 12/12/2022]
Abstract
This review discusses the evidence supporting a role for ATP signaling (operated by P2X and P2Y receptors) and adenosine signaling (mainly operated by A1 and A2A receptors) in the crosstalk between neurons, astrocytes, microglia and oligodendrocytes. An initial emphasis will be given to the cooperation between adenosine receptors to sharpen information salience encoding across synapses. The interplay between ATP and adenosine signaling in the communication between astrocytes and neurons will then be presented in context of the integrative properties of the astrocytic syncytium, allowing to implement heterosynaptic depression processes in neuronal networks. The process of microglia 'activation' and its control by astrocytes and neurons will then be analyzed under the perspective of an interplay between different P2 receptors and adenosine A2A receptors. In spite of these indications of a prominent role of purinergic signaling in the bidirectional communication between neurons and glia, its therapeutical exploitation still awaits obtaining an integrated view of the spatio-temporal action of ATP signaling and adenosine signaling, clearly distinguishing the involvement of both purinergic signaling systems in the regulation of physiological processes and in the control of pathogenic-like responses upon brain dysfunction or damage.
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20
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P2X7 Receptors Amplify CNS Damage in Neurodegenerative Diseases. Int J Mol Sci 2020; 21:ijms21175996. [PMID: 32825423 PMCID: PMC7504621 DOI: 10.3390/ijms21175996] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 08/07/2020] [Accepted: 08/17/2020] [Indexed: 12/11/2022] Open
Abstract
ATP is a (co)transmitter and signaling molecule in the CNS. It acts at a multitude of ligand-gated cationic channels termed P2X to induce rapid depolarization of the cell membrane. Within this receptor-channel family, the P2X7 receptor (R) allows the transmembrane fluxes of Na+, Ca2+, and K+, but also allows the slow permeation of larger organic molecules. This is supposed to cause necrosis by excessive Ca2+ influx, as well as depletion of intracellular ions and metabolites. Cell death may also occur by apoptosis due to the activation of the caspase enzymatic cascade. Because P2X7Rs are localized in the CNS preferentially on microglia, but also at a lower density on neuroglia (astrocytes, oligodendrocytes) the stimulation of this receptor leads to the release of neurodegeneration-inducing bioactive molecules such as pro-inflammatory cytokines, chemokines, proteases, reactive oxygen and nitrogen molecules, and the excitotoxic glutamate/ATP. Various neurodegenerative reactions of the brain/spinal cord following acute harmful events (mechanical CNS damage, ischemia, status epilepticus) or chronic neurodegenerative diseases (neuropathic pain, Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, amyotrophic lateral sclerosis) lead to a massive release of ATP via the leaky plasma membrane of neural tissue. This causes cellular damage superimposed on the original consequences of neurodegeneration. Hence, blood-brain-barrier permeable pharmacological antagonists of P2X7Rs with excellent bioavailability are possible therapeutic agents for these diseases. The aim of this review article is to summarize our present state of knowledge on the involvement of P2X7R-mediated events in neurodegenerative illnesses endangering especially the life quality and duration of the aged human population.
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21
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Zhao Y, Yang J, Li C, Zhou G, Wan H, Ding Z, Wan H, Zhou H. Role of the neurovascular unit in the process of cerebral ischemic injury. Pharmacol Res 2020; 160:105103. [PMID: 32739425 DOI: 10.1016/j.phrs.2020.105103] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 12/17/2022]
Abstract
Cerebral ischemic injury exhibits both high morbidity and mortality worldwide. Traditional research of the pathogenesis of cerebral ischemic injury has focused on separate analyses of the involved cell types. In recent years, the neurovascular unit (NVU) mechanism of cerebral ischemic injury has been proposed in modern medicine. Hence, more effective strategies for the treatment of cerebral ischemic injury may be provided through comprehensive analysis of brain cells and the extracellular matrix. However, recent studies that have investigated the function of the NVU in cerebral ischemic injury have been insufficient. In addition, the metabolism and energy conversion of the NVU depend on interactions among multiple cell types, which make it difficult to identify the unique contribution of each cell type. Therefore, in the present review, we comprehensively summarize the regulatory effects and recovery mechanisms of four major cell types (i.e., astrocytes, microglia, brain-microvascular endothelial cells, and neurons) in the NVU under cerebral ischemic injury, as well as discuss the interactions among these cell types in the NVU. Furthermore, we discuss the common signaling pathways and signaling factors that mediate cerebral ischemic injury in the NVU, which may help to provide a theoretical basis for the comprehensive elucidation of cerebral ischemic injury.
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Affiliation(s)
- Yu Zhao
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, PR China
| | - Jiehong Yang
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, PR China
| | - Chang Li
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, PR China
| | - Guoying Zhou
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, PR China
| | - Haofang Wan
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, PR China
| | - Zhishan Ding
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, PR China
| | - Haitong Wan
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, PR China.
| | - Huifen Zhou
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, PR China.
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22
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Umpierre AD, Bystrom LL, Ying Y, Liu YU, Worrell G, Wu LJ. Microglial calcium signaling is attuned to neuronal activity in awake mice. eLife 2020; 9:56502. [PMID: 32716294 PMCID: PMC7402678 DOI: 10.7554/elife.56502] [Citation(s) in RCA: 102] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Accepted: 07/14/2020] [Indexed: 12/14/2022] Open
Abstract
Microglial calcium signaling underlies a number of key physiological and pathological processes in situ, but has not been studied in vivo in awake mice. Using multiple GCaMP6 variants targeted to microglia, we assessed how microglial calcium signaling responds to alterations in neuronal activity across a wide range. We find that only a small subset of microglial somata and processes exhibited spontaneous calcium transients in a chronic window preparation. However, hyperactive shifts in neuronal activity (kainate status epilepticus and CaMKIIa Gq DREADD activation) triggered increased microglial process calcium signaling, often concomitant with process extension. Additionally, hypoactive shifts in neuronal activity (isoflurane anesthesia and CaMKIIa Gi DREADD activation) also increased microglial process calcium signaling. Under hypoactive neuronal conditions, microglia also exhibited process extension and outgrowth with greater calcium signaling. Our work reveals that microglia have highly distinct microdomain signaling, and that processes specifically respond to bi-directional shifts in neuronal activity through increased calcium signaling.
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Affiliation(s)
| | | | - Yanlu Ying
- Department of Neurology, Mayo Clinic, Rochester, United States
| | - Yong U Liu
- Department of Neurology, Mayo Clinic, Rochester, United States
| | - Gregory Worrell
- Department of Neurology, Mayo Clinic, Rochester, United States
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, United States.,Department of Neuroscience, Mayo Clinic, Jacksonville, United States.,Department of Immunology, Mayo Clinic, Rochester, United States
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23
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Nguyen HM, di Lucente J, Chen YJ, Cui Y, Ibrahim RH, Pennington MW, Jin LW, Maezawa I, Wulff H. Biophysical basis for Kv1.3 regulation of membrane potential changes induced by P2X4-mediated calcium entry in microglia. Glia 2020; 68:2377-2394. [PMID: 32525239 PMCID: PMC7540709 DOI: 10.1002/glia.23847] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 04/17/2020] [Accepted: 05/07/2020] [Indexed: 12/02/2022]
Abstract
Microglia‐mediated inflammation exerts adverse effects in ischemic stroke and in neurodegenerative disorders such as Alzheimer's disease (AD). Expression of the voltage‐gated potassium channel Kv1.3 is required for microglia activation. Both genetic deletion and pharmacological inhibition of Kv1.3 are effective in reducing microglia activation and the associated inflammatory responses, as well as in improving neurological outcomes in animal models of AD and ischemic stroke. Here we sought to elucidate the molecular mechanisms underlying the therapeutic effects of Kv1.3 inhibition, which remain incompletely understood. Using a combination of whole‐cell voltage‐clamp electrophysiology and quantitative PCR (qPCR), we first characterized a stimulus‐dependent differential expression pattern for Kv1.3 and P2X4, a major ATP‐gated cationic channel, both in vitro and in vivo. We then demonstrated by whole‐cell current‐clamp experiments that Kv1.3 channels contribute not only to setting the resting membrane potential but also play an important role in counteracting excessive membrane potential changes evoked by depolarizing current injections. Similarly, the presence of Kv1.3 channels renders microglia more resistant to depolarization produced by ATP‐mediated P2X4 receptor activation. Inhibiting Kv1.3 channels with ShK‐223 completely nullified the ability of Kv1.3 to normalize membrane potential changes, resulting in excessive depolarization and reduced calcium transients through P2X4 receptors. Our report thus links Kv1.3 function to P2X4 receptor‐mediated signaling as one of the underlying mechanisms by which Kv1.3 blockade reduces microglia‐mediated inflammation. While we could confirm previously reported differences between males and females in microglial P2X4 expression, microglial Kv1.3 expression exhibited no gender differences in vitro or in vivo. Main Points The voltage‐gated K+ channel Kv1.3 regulates microglial membrane potential. Inhibition of Kv1.3 depolarizes microglia and reduces calcium entry mediated by P2X4 receptors by dissipating the electrochemical driving force for calcium.
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Affiliation(s)
- Hai M Nguyen
- Department of Pharmacology, University of California, Davis, California, USA
| | - Jacopo di Lucente
- Department of Pathology and Laboratory Medicine and M.I.N.D. Institute, University of California Davis Medical Center, Sacramento, California, USA
| | - Yi-Je Chen
- Department of Pharmacology, University of California, Davis, California, USA
| | - Yanjun Cui
- Department of Pharmacology, University of California, Davis, California, USA
| | - Rania H Ibrahim
- Department of Pharmacology, University of California, Davis, California, USA
| | | | - Lee-Way Jin
- Department of Pathology and Laboratory Medicine and M.I.N.D. Institute, University of California Davis Medical Center, Sacramento, California, USA
| | - Izumi Maezawa
- Department of Pathology and Laboratory Medicine and M.I.N.D. Institute, University of California Davis Medical Center, Sacramento, California, USA
| | - Heike Wulff
- Department of Pharmacology, University of California, Davis, California, USA
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24
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Ma H, Su D, Wang Q, Chong Z, Zhu Q, He W, Wang W. Phoenixin 14 inhibits ischemia/reperfusion-induced cytotoxicity in microglia. Arch Biochem Biophys 2020; 689:108411. [PMID: 32450066 DOI: 10.1016/j.abb.2020.108411] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 05/15/2020] [Accepted: 05/17/2020] [Indexed: 12/23/2022]
Abstract
The process of ischemia/reperfusion (IR) in ischemic stroke often leads to significant cell death and permanent neuronal damage. Safe and effective treatments are urgently needed to mitigate the damage caused by IR injury. The naturally occurring pleiotropic peptide phoenixin 14 (PNX-14) has recently come to light as a potential treatment for IR injury. In the present study, we examined the effects of PNX-14 on several key processes involved in ischemic injury, such as pro-inflammatory cytokine expression, oxidative stress, and the related cascade mediated through the toll-like receptor 4 (TLR4) pathway, using BV2 microglia exposed to oxygen-glucose deprivation and reoxygenation (OGD/R). Our results demonstrate an acute ability of PNX-14 to regulate the expression levels of proinflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6). PNX-14 also prevented oxidative stress by reducing the generation of reactive oxygen species (ROS) and increasing the level of the antioxidant glutathione (GSH). Importantly, PNX-14 inhibited high-mobility group box 1 (HMGB1)/TLR4/myeloid differentiation primary response 88 (MyD88)/nuclear factor-κB (NF-κB) signaling pathway, by inhibiting the activation of TLR4 and preventing the nuclear translocation of p65 protein. We further confirmed the cerebroprotective effects of PNX-14 in an MCAO rat model, which resulted in reduced infarct volume and decreased microglia activation. Together, the results of this study implicate a possible protective role of PNX-14 against various aspects of IR injury in vitro.
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Affiliation(s)
- Hongling Ma
- Department of Neurology, Liaocheng People's Hospital of Shandong First Medical University, Liaocheng City, Shandong Province, 252000, China
| | - Daoqing Su
- Department of Neurosurgery, Liaocheng People's Hospital of Shandong First Medical University, Liaocheng City, Shandong Province, 252000, China
| | - Qingdong Wang
- Department of Neurology, Liaocheng People's Hospital of Shandong First Medical University, Liaocheng City, Shandong Province, 252000, China
| | - Zonglei Chong
- Department of Neurosurgery, Liaocheng People's Hospital of Shandong First Medical University, Liaocheng City, Shandong Province, 252000, China
| | - Qiushi Zhu
- Department of Neurosurgery, Liaocheng People's Hospital of Shandong First Medical University, Liaocheng City, Shandong Province, 252000, China
| | - Weibin He
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan City, Hubei Province, 430060, China
| | - Wei Wang
- Department of Neurology, Liaocheng People's Hospital of Shandong First Medical University, Liaocheng City, Shandong Province, 252000, China.
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25
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Belov Kirdajova D, Kriska J, Tureckova J, Anderova M. Ischemia-Triggered Glutamate Excitotoxicity From the Perspective of Glial Cells. Front Cell Neurosci 2020; 14:51. [PMID: 32265656 PMCID: PMC7098326 DOI: 10.3389/fncel.2020.00051] [Citation(s) in RCA: 171] [Impact Index Per Article: 42.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 02/21/2020] [Indexed: 12/21/2022] Open
Abstract
A plethora of neurological disorders shares a final common deadly pathway known as excitotoxicity. Among these disorders, ischemic injury is a prominent cause of death and disability worldwide. Brain ischemia stems from cardiac arrest or stroke, both responsible for insufficient blood supply to the brain parenchyma. Glucose and oxygen deficiency disrupts oxidative phosphorylation, which results in energy depletion and ionic imbalance, followed by cell membrane depolarization, calcium (Ca2+) overload, and extracellular accumulation of excitatory amino acid glutamate. If tight physiological regulation fails to clear the surplus of this neurotransmitter, subsequent prolonged activation of glutamate receptors forms a vicious circle between elevated concentrations of intracellular Ca2+ ions and aberrant glutamate release, aggravating the effect of this ischemic pathway. The activation of downstream Ca2+-dependent enzymes has a catastrophic impact on nervous tissue leading to cell death, accompanied by the formation of free radicals, edema, and inflammation. After decades of “neuron-centric” approaches, recent research has also finally shed some light on the role of glial cells in neurological diseases. It is becoming more and more evident that neurons and glia depend on each other. Neuronal cells, astrocytes, microglia, NG2 glia, and oligodendrocytes all have their roles in what is known as glutamate excitotoxicity. However, who is the main contributor to the ischemic pathway, and who is the unsuspecting victim? In this review article, we summarize the so-far-revealed roles of cells in the central nervous system, with particular attention to glial cells in ischemia-induced glutamate excitotoxicity, its origins, and consequences.
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Affiliation(s)
- Denisa Belov Kirdajova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic (ASCR), Prague, Czechia.,Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Jan Kriska
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic (ASCR), Prague, Czechia.,Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Jana Tureckova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic (ASCR), Prague, Czechia
| | - Miroslava Anderova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic (ASCR), Prague, Czechia.,Second Faculty of Medicine, Charles University, Prague, Czechia
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26
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Gheorghe RO, Deftu A, Filippi A, Grosu A, Bica-Popi M, Chiritoiu M, Chiritoiu G, Munteanu C, Silvestro L, Ristoiu V. Silencing the Cytoskeleton Protein Iba1 (Ionized Calcium Binding Adapter Protein 1) Interferes with BV2 Microglia Functioning. Cell Mol Neurobiol 2020; 40:1011-1027. [PMID: 31950314 DOI: 10.1007/s10571-020-00790-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 01/07/2020] [Indexed: 01/31/2023]
Abstract
Iba1 (ionized calcium binding adapter protein 1) is a cytoskeleton protein specific only for microglia and macrophages, where it acts as an actin-cross linking protein. Although frequently regarded as a marker of activation, its involvement in cell migration, membrane ruffling, phagocytosis or in microglia remodeling during immunological surveillance of the brain suggest that Iba1 is not a simple cytoskeleton protein, but a signaling molecule involved in specific signaling pathways. In this study we investigated if Iba1 could also represent a drug target, and tested the hypothesis that its specific silencing with customized Iba1-siRNA can modulate microglia functioning. The results showed that Iba1-silenced BV2 microglia migrate less due to reduced proliferation and cell adhesion, while their phagocytic activity and P2x7 functioning was significantly increased. Our data are the proof of concept that Iba1 protein is a new microglia target, which opens a new therapeutic avenue for modulating microglia behavior.
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Affiliation(s)
- Roxana-Olimpia Gheorghe
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Splaiul Independentei 91-95, Sector 5, 050095, Bucharest, Romania
| | - Alexandru Deftu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Splaiul Independentei 91-95, Sector 5, 050095, Bucharest, Romania
| | - Alexandru Filippi
- Institute of Cellular Biology and Pathology 'Nicolae Simionescu' of the Romanian Academy, Bucharest, Romania
| | - Andreea Grosu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Splaiul Independentei 91-95, Sector 5, 050095, Bucharest, Romania
| | - Melania Bica-Popi
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Splaiul Independentei 91-95, Sector 5, 050095, Bucharest, Romania
| | - Marioara Chiritoiu
- Department of Molecular Cell Biology, Institute of Biochemistry, Romanian Academy, Splaiul Independentei 296, 06003, Bucharest, Romania
| | - Gabriela Chiritoiu
- Department of Molecular Cell Biology, Institute of Biochemistry, Romanian Academy, Splaiul Independentei 296, 06003, Bucharest, Romania
| | - Cristian Munteanu
- Department of Molecular Cell Biology, Institute of Biochemistry, Romanian Academy, Splaiul Independentei 296, 06003, Bucharest, Romania
| | - Luigi Silvestro
- Pharma Serv International, Sabinelor 52, 050853, Bucharest, Romania
| | - Violeta Ristoiu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Splaiul Independentei 91-95, Sector 5, 050095, Bucharest, Romania.
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27
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Eyo UB, Wu LJ. Microglia: Lifelong patrolling immune cells of the brain. Prog Neurobiol 2019; 179:101614. [PMID: 31075285 DOI: 10.1016/j.pneurobio.2019.04.003] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 04/11/2019] [Accepted: 04/19/2019] [Indexed: 02/02/2023]
Abstract
Microglial cells are the predominant parenchymal immune cell of the brain. Recent evidence suggests that like peripheral immune cells, microglia patrol the brain in health and disease. Reviewing these data, we first examine the evidence that microglia invade the brain mesenchyme early in embryonic development, establish residence therein, proliferate and subsequently maintain their numbers throughout life. We, then, summarize established and novel evidence for microglial process surveillance in the healthy and injured brain. Finally, we discuss emerging evidence for microglial cell body dynamics that challenge existing assumptions of their sessile nature. We conclude that microglia are long-lived immune cells that patrol the brain through both cell body and process movements. This recognition has significant implications for neuroimmune interactions throughout the animal lifespan.
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Affiliation(s)
- Ukpong B Eyo
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA; Center for Brain Immunology and Glia (BIG), University of Virginia, Charlottesville, VA, USA; Department of Neuroscience, University of Virginia, Charlottesville, VA, USA
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA; Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Department of Immunology, Mayo Clinic, Rochester, MN 55905, USA.
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28
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Dispelling myths about connexins, pannexins and P2X7 in hypoxic-ischemic central nervous system. Neurosci Lett 2019; 695:76-85. [PMID: 29195910 DOI: 10.1016/j.neulet.2017.11.044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 10/07/2017] [Accepted: 11/21/2017] [Indexed: 01/17/2023]
Abstract
In membrane physiology, as in other fields, myths or speculations may be repeated so often and so widely that they are perceived as facts. To some extent, this has occurred with regard to gap junctions, hemichannels, pannexin channels and P2X7 (ionotropic receptors), especially concerning the interpretation of the individual role of these channels in hypoxic-ischemic CNS since these channels may be closed by the same pharmacological blockers. Significance of existing controversial data are highlighted and contradictory views from different groups are critically discussed herein.
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29
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Microglial cell loss after ischemic stroke favors brain neutrophil accumulation. Acta Neuropathol 2019; 137:321-341. [PMID: 30580383 PMCID: PMC6513908 DOI: 10.1007/s00401-018-1954-4] [Citation(s) in RCA: 165] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 12/18/2018] [Accepted: 12/19/2018] [Indexed: 12/20/2022]
Abstract
Stroke attracts neutrophils to the injured brain tissue where they can damage the integrity of the blood-brain barrier and exacerbate the lesion. However, the mechanisms involved in neutrophil transmigration, location and accumulation in the ischemic brain are not fully elucidated. Neutrophils can reach the perivascular spaces of brain vessels after crossing the endothelial cell layer and endothelial basal lamina of post-capillary venules, or migrating from the leptomeninges following pial vessel extravasation and/or a suggested translocation from the skull bone marrow. Based on previous observations of microglia phagocytosing neutrophils recruited to the ischemic brain lesion, we hypothesized that microglial cells might control neutrophil accumulation in the injured brain. We studied a model of permanent occlusion of the middle cerebral artery in mice, including microglia- and neutrophil-reporter mice. Using various in vitro and in vivo strategies to impair microglial function or to eliminate microglia by targeting colony stimulating factor 1 receptor (CSF1R), this study demonstrates that microglial phagocytosis of neutrophils has fundamental consequences for the ischemic tissue. We found that reactive microglia engulf neutrophils at the periphery of the ischemic lesion, whereas local microglial cell loss and dystrophy occurring in the ischemic core are associated with the accumulation of neutrophils first in perivascular spaces and later in the parenchyma. Accordingly, microglia depletion by long-term treatment with a CSF1R inhibitor increased the numbers of neutrophils and enlarged the ischemic lesion. Hence, microglial phagocytic function sets a critical line of defense against the vascular and tissue damaging capacity of neutrophils in brain ischemia.
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30
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Kyrargyri V, Attwell D, Jolivet RB, Madry C. Analysis of Signaling Mechanisms Regulating Microglial Process Movement. Methods Mol Biol 2019; 2034:191-205. [PMID: 31392686 DOI: 10.1007/978-1-4939-9658-2_14] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Microglia, the brain's innate immune cells, are extremely motile cells, continuously surveying the central nervous system (CNS) to serve homeostatic functions and to respond to pathological events. In the healthy brain, microglia exhibit a small cell body with long, branched, and highly motile processes, which constantly extend and retract, effectively "patrolling" the brain parenchyma. Over the last decade, methodological advances in microscopy and the availability of genetically encoded reporter mice have allowed us to probe microglial physiology in situ. Beyond their classical immunological roles, unexpected functions of microglia have been revealed, both in the developing and the adult brain: microglia regulate the generation of newborn neurons, control the formation and elimination of synapses, and modulate neuronal activity. Many of these newly ascribed functions depend directly on microglial process movement. Thus, elucidating the mechanisms underlying microglial motility is of great importance to understand their role in brain physiology and pathophysiology. Two-photon imaging of fluorescently labeled microglia, either in vivo or ex vivo in acute brain slices, has emerged as an indispensable tool for investigating microglial movements and their functional consequences. This chapter aims to provide a detailed description of the experimental data acquisition and analysis needed to address these questions, with a special focus on key dynamic and morphological metrics such as surveillance, directed motility, and ramification.
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Affiliation(s)
- Vasiliki Kyrargyri
- Department of Immunology, Laboratory of Molecular Genetics, Hellenic Pasteur Institute, Athens, Greece
| | - David Attwell
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Renaud Blaise Jolivet
- Département de Physique Nucléaire et Corpusculaire, University of Geneva, Geneva, Switzerland
- CERN, Geneva, Switzerland
| | - Christian Madry
- Institute of Neurophysiology, Charité-Universitätsmedizin, Berlin, Germany.
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31
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Zhao H, Chen Y, Feng H. P2X7 Receptor-Associated Programmed Cell Death in the Pathophysiology of Hemorrhagic Stroke. Curr Neuropharmacol 2018; 16:1282-1295. [PMID: 29766811 PMCID: PMC6251042 DOI: 10.2174/1570159x16666180516094500] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Revised: 07/17/2017] [Accepted: 02/28/2018] [Indexed: 12/20/2022] Open
Abstract
Hemorrhagic stroke is a life-threatening disease characterized by a sudden rupture of cerebral blood vessels, and cell death is widely believed to occur after exposure to blood metabolites or subsequently damaged cells. Recently, programmed cell death, such as apoptosis, autophagy, necroptosis, pyroptosis, and ferroptosis, has been demonstrated to play crucial roles in the pathophysiology of stroke. However, the detailed mechanisms of these novel kinds of cell death are still unclear. The P2X7 receptor, previously known for its cytotoxic activity, is an ATP-gated, nonselective cation channel that belongs to the family of ionotropic P2X receptors. Evolving evidence indicates that the P2X7 receptor plays a pivotal role in central nervous system pathology; genetic deletion and pharmacological blockade of the P2X7 receptor provide neuroprotection in various neurological disorders, including intracerebral hemorrhage and subarachnoid hemorrhage. The P2X7 receptor may regulate programmed cell death via (I) exocytosis of secretory lysosomes, (II) exocytosis of autophagosomes or autophagolysosomes during formation of the initial autophagic isolation membrane or omegasome, and (III) direct release of cytosolic IL-1β secondary to regulated cell death by pyroptosis or necroptosis. In this review, we present an overview of P2X7 receptor- associated programmed cell death for further understanding of hemorrhagic stroke pathophysiology, as well as potential therapeutic targets for its treatment.
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Affiliation(s)
- Hengli Zhao
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Yujie Chen
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Hua Feng
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Chongqing, China
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32
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Koole M, Schmidt ME, Hijzen A, Ravenstijn P, Vandermeulen C, Van Weehaeghe D, Serdons K, Celen S, Bormans G, Ceusters M, Zhang W, Van Nueten L, Kolb H, de Hoon J, Van Laere K. 18F-JNJ-64413739, a Novel PET Ligand for the P2X7 Ion Channel: Radiation Dosimetry, Kinetic Modeling, Test-Retest Variability, and Occupancy of the P2X7 Antagonist JNJ-54175446. J Nucl Med 2018; 60:683-690. [PMID: 30262518 DOI: 10.2967/jnumed.118.216747] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 09/18/2018] [Indexed: 12/27/2022] Open
Abstract
The P2X7 receptor (P2X7R) is an adenosine triphosphate-gated ion channel that is predominantly expressed on microglial cells in the central nervous system. We report the clinical qualification of P2X7-specific PET ligand 18F-JNJ-64413739 in healthy volunteers, including dosimetry, kinetic modeling, test-retest variability, and blocking by the P2X7 antagonist JNJ-54175446. Methods: Whole-body dosimetry was performed in 3 healthy male subjects by consecutive whole-body PET/CT scanning, estimation of the normalized cumulated activity, and calculation of the effective dose using OLINDA (v1.1). Next, 5 healthy male subjects underwent a 120-min dynamic 18F-JNJ-64413739 PET/MRI scan with arterial blood sampling to determine the appropriate kinetic model. For this purpose, 1- and 2-tissue compartment models and Logan graphic analysis (LGA) were evaluated for estimating regional volumes of distribution (VT). PET/MRI scanning was repeated in 4 of these subjects to evaluate medium-term test-retest variability (interscan interval, 26-97 d). For the single-dose occupancy study, 8 healthy male subjects underwent baseline and postdose 18F-JNJ-64413739 PET/MRI scans 4-6 h after the administration of a single oral dose of JNJ-54175446 (dose range, 5-300 mg). P2X7 occupancies were estimated using a Lassen plot and regional baseline and postdose VT Results: The average (mean ± SD) effective dose was 22.0 ± 1.0 μSv/MBq. The 2-tissue compartment model was the most appropriate kinetic model, with LGA showing very similar results. Regional 2-tissue compartment model VT values were about 3 and were rather homogeneous across all brain regions, with slightly higher estimates for the thalamus, striatum, and brain stem. Between-subject VT variability was relatively high, with cortical VT showing an approximate 3-fold range across subjects. As for time stability, the acquisition time could be reduced to 90 min. The average regional test-retest variability values were 10.7% ± 2.2% for 2-tissue compartment model VT and 11.9% ± 2.2% for LGA VT P2X7 occupancy approached saturation for single doses of JNJ-54175446 higher than 50 mg, and no reference region could be identified. Conclusion: 18F-JNJ-64413739 is a suitable PET ligand for the quantification of P2X7R expression in the human brain. It can be used to provide insight into P2X7R expression in health and disease, to evaluate target engagement by P2X7 antagonists, and to guide dose selection.
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Affiliation(s)
- Michel Koole
- Division of Nuclear Medicine and Molecular Imaging, University Hospitals Leuven, Leuven, Belgium.,Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | | | - Anja Hijzen
- Janssen Research and Development, Beerse, Belgium
| | | | - Corinne Vandermeulen
- Center for Clinical Pharmacology, University Hospitals Leuven, Leuven, Belgium; and
| | - Donatienne Van Weehaeghe
- Division of Nuclear Medicine and Molecular Imaging, University Hospitals Leuven, Leuven, Belgium
| | - Kim Serdons
- Division of Nuclear Medicine and Molecular Imaging, University Hospitals Leuven, Leuven, Belgium
| | - Sofie Celen
- Laboratory for Radiopharmaceutical Research, KU Leuven, Leuven, Belgium
| | - Guy Bormans
- Laboratory for Radiopharmaceutical Research, KU Leuven, Leuven, Belgium
| | | | - Wei Zhang
- Janssen Research and Development, Beerse, Belgium
| | | | | | - Jan de Hoon
- Center for Clinical Pharmacology, University Hospitals Leuven, Leuven, Belgium; and
| | - Koen Van Laere
- Division of Nuclear Medicine and Molecular Imaging, University Hospitals Leuven, Leuven, Belgium .,Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
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33
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Paternò R, Chillon JM. Potentially Common Therapeutic Targets for Multiple Sclerosis and Ischemic Stroke. Front Physiol 2018; 9:855. [PMID: 30057552 PMCID: PMC6053536 DOI: 10.3389/fphys.2018.00855] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 06/15/2018] [Indexed: 12/21/2022] Open
Abstract
Ischemic stroke (IS) and multiple sclerosis (MS) are two pathologies of the central nervous system (CNS). At the first look, this appears to be the only similarity between the two diseases, as they seem quite different. Indeed IS has an acute onset compared to MS which develops chronically; IS is consecutive to blood clot migrating to cerebral blood vessels or decrease in cerebral blood flow following atherosclerosis or decreases in cardiac output, whereas MS is an immune disease associated with neurodegeneration. However, both pathologies share similar pathologic pathways and treatments used in MS have been the object of studies in IS. In this mini-review we will discuss similarities between IS and MS on astrocytes and neuroinflammation hallmarks emphasizing the potential for treatments.
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Affiliation(s)
- Roberto Paternò
- Dipartimento di Medicina Clinica e Chirurgia, Università degli Studi di Napoli Federico II, Naples, Italy
| | - Jean-Marc Chillon
- Mécanismes Physiopathologiques et Conséquences des Calcifications Cardiovasculaires (EA 7517), Faculty of Pharmacy, University of Picardie Jules Verne, Amiens, France.,Direction de la Recherche Clinique et de l'Innovation, CHU Amiens Picardie, Amiens, France
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Vats K, Sarmah D, Kaur H, Wanve M, Kalia K, Borah A, Dave KR, Yavagal DR, Bhattacharya P. Inflammasomes in stroke: a triggering role for acid-sensing ion channels. Ann N Y Acad Sci 2018; 1431:14-24. [DOI: 10.1111/nyas.13852] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 04/21/2018] [Accepted: 04/23/2018] [Indexed: 01/23/2023]
Affiliation(s)
- Kanchan Vats
- Department of Pharmacology and Toxicology; National Institute of Pharmaceutical Education and Research (NIPER) Ahmedabad; Gandhinagar Gujarat India
| | - Deepaneeta Sarmah
- Department of Pharmacology and Toxicology; National Institute of Pharmaceutical Education and Research (NIPER) Ahmedabad; Gandhinagar Gujarat India
| | - Harpreet Kaur
- Department of Pharmacology and Toxicology; National Institute of Pharmaceutical Education and Research (NIPER) Ahmedabad; Gandhinagar Gujarat India
| | - Madhuri Wanve
- Department of Pharmacology and Toxicology; National Institute of Pharmaceutical Education and Research (NIPER) Ahmedabad; Gandhinagar Gujarat India
| | - Kiran Kalia
- Department of Pharmacology and Toxicology; National Institute of Pharmaceutical Education and Research (NIPER) Ahmedabad; Gandhinagar Gujarat India
| | - Anupom Borah
- Cellular and Molecular Neurobiology Laboratory; Department of Life Science and Bioinformatics; Assam University; Silchar Assam India
| | - Kunjan R. Dave
- Department of Neurology; University of Miami Miller School of Medicine; Miami Florida
| | - Dileep R. Yavagal
- Department of Neurology; University of Miami Miller School of Medicine; Miami Florida
| | - Pallab Bhattacharya
- Department of Pharmacology and Toxicology; National Institute of Pharmaceutical Education and Research (NIPER) Ahmedabad; Gandhinagar Gujarat India
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Madry C, Arancibia-Cárcamo IL, Kyrargyri V, Chan VTT, Hamilton NB, Attwell D. Effects of the ecto-ATPase apyrase on microglial ramification and surveillance reflect cell depolarization, not ATP depletion. Proc Natl Acad Sci U S A 2018; 115:E1608-E1617. [PMID: 29382767 PMCID: PMC5816168 DOI: 10.1073/pnas.1715354115] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Microglia, the brain's innate immune cells, have highly motile processes which constantly survey the brain to detect infection, remove dying cells, and prune synapses during brain development. ATP released by tissue damage is known to attract microglial processes, but it is controversial whether an ambient level of ATP is needed to promote constant microglial surveillance in the normal brain. Applying the ATPase apyrase, an enzyme which hydrolyzes ATP and ADP, reduces microglial process ramification and surveillance, suggesting that ambient ATP/ADP maintains microglial surveillance. However, attempting to raise the level of ATP/ADP by blocking the endogenous ecto-ATPase (termed NTPDase1/CD39), which also hydrolyzes ATP/ADP, does not affect the cells' ramification or surveillance, nor their membrane currents, which respond to even small rises of extracellular [ATP] or [ADP] with the activation of K+ channels. This indicates a lack of detectable ambient ATP/ADP and ecto-ATPase activity, contradicting the results with apyrase. We resolve this contradiction by demonstrating that contamination of commercially available apyrase by a high K+ concentration reduces ramification and surveillance by depolarizing microglia. Exposure to the same K+ concentration (without apyrase added) reduced ramification and surveillance as with apyrase. Dialysis of apyrase to remove K+ retained its ATP-hydrolyzing activity but abolished the microglial depolarization and decrease of ramification produced by the undialyzed enzyme. Thus, applying apyrase affects microglia by an action independent of ATP, and no ambient purinergic signaling is required to maintain microglial ramification and surveillance. These results also have implications for hundreds of prior studies that employed apyrase to hydrolyze ATP/ADP.
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Affiliation(s)
- Christian Madry
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom;
- Institute of Neurophysiology, Charité Universitätsmedizin, 10117 Berlin, Germany
| | - I Lorena Arancibia-Cárcamo
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom
| | - Vasiliki Kyrargyri
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom
| | - Victor T T Chan
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom
| | - Nicola B Hamilton
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom;
- Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UL, United Kingdom
| | - David Attwell
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom;
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Coordinate effects of P2X7 and extracellular acidification in microglial cells. Oncotarget 2018; 9:12718-12731. [PMID: 29560104 PMCID: PMC5849168 DOI: 10.18632/oncotarget.24331] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 01/24/2018] [Indexed: 12/26/2022] Open
Abstract
Extracellular adenosine 5′-triphosphate (ATP) is a damage-associated molecular pattern and contributes to inflammation associated diseases including cancer. Extracellular acidosis is a novel danger signal in the inflammatory sites, where it can modulate inflammation, immunity and tumor growth. Extracellular acidification was shown to inhibit P2X7-mediated channel currents, while it remains unknown how acidification and P2X7 together affect cellular responses. Here, we treated BV-2 microglial cells with ATP in a short period (<15 min) or a sustained acidified condition. For short acidification we compared the actions of neutralized ATP and acidic ATP in a condition with pH buffering. For sustained acidification, we treated cells with neutralized ATP in acidic medium or acidic ATP in medium without pH buffering. In the short acidified condition, neutralized ATP induced higher responses than acidic ATP to increase intracellular calcium and reactive oxygen species, decrease intracellular potassium and induce cell death. In contrast, these cellular responses and mitochondrial fission caused by neutralized ATP were enhanced by pH 6.0 and pH 4.5 media. P2X7 activation can also rapidly block mitochondrial ATP turnover and respiration capacity, both of which were mimicked by nigericin and enhanced by acidity. Taken together P2X7-mediated ionic fluxes and reactive oxygen species production are attenuated under short acidification, while sustained acidification itself can induce mitochondrial toxicity which deteriorates the mitochondrial function under P2X7 activation.
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Neuronal P2X7 receptor-induced reactive oxygen species production contributes to nociceptive behavior in mice. Sci Rep 2017; 7:3539. [PMID: 28615626 PMCID: PMC5471238 DOI: 10.1038/s41598-017-03813-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 05/03/2017] [Indexed: 11/27/2022] Open
Abstract
ATP can activate a variety of pathways through P2 purinoreceptors, leading to neuroprotection and pathology in the CNS. Among all P2X receptors, the P2X7 receptor (P2X7R) is a well-defined therapeutic target for inflammatory and neuropathic pain. Activation of P2X7R can generate reactive oxygen species (ROS) in macrophages and microglia. However, the role of ROS in P2X7R–induced pain remains unexplored. Here, we investigated the downstream effects of neuronal P2X7R activation in the spinal cord. We found that ATP induces ROS production in spinal cord dorsal horn neurons, an effect eliminated by ROS scavenger N-tert-butyl-α-phenylnitrone (PBN) and P2X7R antagonist A438079. A similar effect was observed with a P2X7R agonist, BzATP, and was attenuated by a NADPH oxidase inhibitor apocynin. Intrathecal administration of BzATP resulted in ROS production in the spinal cord and oxidative DNA damage in dorsal horn neurons. BzATP also induced robust biphasic spontaneous nociceptive behavior. Pre-treatment with A438079 abolished all BzATP-induced nociceptive behaviors, while ROS scavengers dose-dependently attenuated the secondary response. Here, we provide evidence that neuronal P2X7R activation leads to ROS production and subsequent nociceptive pain in mice. Together, the data indicate that P2X7R-induced ROS play a critical role in the P2X7R signaling pathway of the CNS.
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Churchward MA, Tchir DR, Todd KG. Microglial Function during Glucose Deprivation: Inflammatory and Neuropsychiatric Implications. Mol Neurobiol 2017; 55:1477-1487. [PMID: 28176274 PMCID: PMC5820372 DOI: 10.1007/s12035-017-0422-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Accepted: 01/25/2017] [Indexed: 12/23/2022]
Abstract
Inflammation is increasingly recognized as a contributor to the pathophysiology of neuropsychiatric disorders, including depression, anxiety disorders and autism, though the factors leading to contextually inappropriate or sustained inflammation in pathological conditions are yet to be elucidated. Microglia, as the key mediators of inflammation in the CNS, serve as likely candidates in initiating pathological inflammation and as an ideal point of therapeutic intervention. Glucose deprivation, as a component of the pathophysiology of ischemia or occurring transiently in diabetes, may serve to modify microglial function contributing to inflammatory injury. To this end, primary microglia were cultured from postnatal rat brain and subject to glucose deprivation in vitro. Microglia were characterized for their proliferation, phagocytic function and secretion of inflammatory factors, and tested for their capacity to respond to a potent inflammatory stimulus. In the absence of glucose, microglia remained capable of proliferation, phagocytosis and inflammatory activation and showed increased release of inflammatory factors after presentation of an inflammatory stimulus. Glucose-deprived microglia demonstrated increased phagocytic activity and decreased accumulation of lipids in lipid droplets over a 48-h timecourse, suggesting they may use scavenged lipids as a key alternate energy source during metabolic stress. In the present manuscript, we present novel findings that glucose deprivation may sensitize microglial release of inflammatory mediators and prime microglial functions for both survival and inflammatory roles, which may contribute to psychiatric comorbidities of ischemia, diabetes and/or metabolic disorder.
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Affiliation(s)
- Matthew A Churchward
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, 116th St and 85th Ave NW, Edmonton, AB T6G2R3, Canada
| | - Devan R Tchir
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, 116th St and 85th Ave NW, Edmonton, AB T6G2R3, Canada
| | - Kathryn G Todd
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, 116th St and 85th Ave NW, Edmonton, AB T6G2R3, Canada. .,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB T6G 2R3, Canada.
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40
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Caseley EA, Muench SP, Fishwick CW, Jiang LH. Structure-based identification and characterisation of structurally novel human P2X7 receptor antagonists. Biochem Pharmacol 2016; 116:130-9. [PMID: 27481062 PMCID: PMC5012888 DOI: 10.1016/j.bcp.2016.07.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 07/28/2016] [Indexed: 12/13/2022]
Abstract
The P2X7 receptor (P2X7R) plays an important role in diverse conditions associated with tissue damage and inflammation, meaning that the human P2X7R (hP2X7R) is an attractive therapeutic target. The crystal structures of the zebrafish P2X4R in the closed and ATP-bound open states provide an unprecedented opportunity for structure-guided identification of new ligands. The present study performed virtual screening of ∼100,000 structurally diverse compounds against the ATP-binding pocket in the hP2X7R. This identified three compounds (C23, C40 and C60) out of 73 top-ranked compounds by testing against hP2X7R-mediated Ca(2+) responses. These compounds were further characterised using Ca(2+) imaging, patch-clamp current recording, YO-PRO-1 uptake and propidium iodide cell death assays. All three compounds inhibited BzATP-induced Ca(2+) responses concentration-dependently with IC50s of 5.1±0.3μM, 4.8±0.8μM and 3.2±0.2μM, respectively. C23 and C40 inhibited BzATP-induced currents in a reversible and concentration-dependent manner, with IC50s of 0.35±0.3μM and 1.2±0.1μM, respectively, but surprisingly C60 did not affect BzATP-induced currents up to 100μM. They suppressed BzATP-induced YO-PRO-1 uptake with IC50s of 1.8±0.9μM, 1.0±0.1μM and 0.8±0.2μM, respectively. Furthermore, these three compounds strongly protected against ATP-induced cell death. Among them, C40 and C60 exhibited strong specificity towards the hP2X7R over the hP2X4R and rP2X3R. In conclusion, our study reports the identification of three novel hP2X7R antagonists with micromolar potency for the first time using a structure-based approach, including the first P2X7R antagonist with preferential inhibition of large pore formation.
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MESH Headings
- Adenosine Triphosphate/analogs & derivatives
- Adenosine Triphosphate/chemistry
- Adenosine Triphosphate/metabolism
- Adenosine Triphosphate/pharmacology
- Amides/chemistry
- Amides/metabolism
- Amides/pharmacology
- Animals
- Anti-Inflammatory Agents, Non-Steroidal/chemistry
- Anti-Inflammatory Agents, Non-Steroidal/metabolism
- Anti-Inflammatory Agents, Non-Steroidal/pharmacology
- Binding Sites
- Calcium Signaling/drug effects
- HEK293 Cells
- Hepatocytes/cytology
- Hepatocytes/drug effects
- Hepatocytes/metabolism
- Humans
- Image Processing, Computer-Assisted
- Indoles/chemistry
- Indoles/metabolism
- Indoles/pharmacology
- Ligands
- Microscopy, Fluorescence
- Models, Molecular
- Patch-Clamp Techniques
- Purinergic P2X Receptor Antagonists/chemistry
- Purinergic P2X Receptor Antagonists/metabolism
- Purinergic P2X Receptor Antagonists/pharmacology
- Rats
- Receptors, Purinergic P2X3/chemistry
- Receptors, Purinergic P2X3/genetics
- Receptors, Purinergic P2X3/metabolism
- Receptors, Purinergic P2X4/chemistry
- Receptors, Purinergic P2X4/genetics
- Receptors, Purinergic P2X4/metabolism
- Receptors, Purinergic P2X7/chemistry
- Receptors, Purinergic P2X7/genetics
- Receptors, Purinergic P2X7/metabolism
- Recombinant Proteins/chemistry
- Recombinant Proteins/metabolism
- Single-Cell Analysis
- Small Molecule Libraries
- Structure-Activity Relationship
- Thiophenes/chemistry
- Thiophenes/metabolism
- Thiophenes/pharmacology
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Affiliation(s)
- Emily A Caseley
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, UK
| | - Stephen P Muench
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, UK
| | | | - Lin-Hua Jiang
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, UK.
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41
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Infiltrating cells from host brain restore the microglial population in grafted cortical tissue. Sci Rep 2016; 6:33080. [PMID: 27615195 PMCID: PMC5018877 DOI: 10.1038/srep33080] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/19/2016] [Indexed: 12/20/2022] Open
Abstract
Transplantation of embryonic cortical tissue is considered as a promising therapy for brain injury. Grafted neurons can reestablish neuronal network and improve cortical function of the host brain. Microglia is a key player in regulating neuronal survival and plasticity, but its activation and dynamics in grafted cortical tissue remain unknown. Using two-photon intravital imaging and parabiotic model, here we investigated the proliferation and source of microglia in the donor region by transplanting embryonic cortical tissue into adult cortex. Live imaging showed that the endogenous microglia of the grafted tissue were rapidly lost after transplantation. Instead, host-derived microglia infiltrated and colonized the graft. Parabiotic model suggested that the main source of infiltrating cells is the parenchyma of the host brain. Colonized microglia proliferated and experienced an extensive morphological transition and eventually differentiated into resting ramified morphology. Collectively, these results demonstrated that donor tissue has little contribution to the activated microglia and host brain controls the microglial population in the graft.
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Bhattacharya A, Biber K. The microglial ATP-gated ion channel P2X7 as a CNS drug target. Glia 2016; 64:1772-87. [PMID: 27219534 DOI: 10.1002/glia.23001] [Citation(s) in RCA: 151] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 04/17/2016] [Accepted: 04/18/2016] [Indexed: 12/14/2022]
Abstract
Based on promising preclinical evidence, microglial P2X7 has increasingly being recognized as a target for therapeutic intervention in neurological and psychiatric diseases. However, despite this knowledge no P2X7-related drug has yet entered clinical trials with respect to CNS diseases. We here discuss the current literature on P2X7 being a drug target and identify unsolved issues and still open questions that have hampered the development of P2X7 dependent therapeutic approaches for CNS diseases. It is concluded here that the lack of brain penetrating P2X7 antagonists is a major obstacle in the field and that central P2X7 is a yet untested clinical drug target. In the CNS, microglial P2X7 activation causes neuroinflammation, which in turn plays a role in various CNS disorders. This has resulted in a surge of brain penetrant P2X7 antagonists. P2X7 is a viable, clinically untested CNS drug target. GLIA 2016;64:1772-1787.
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Affiliation(s)
- Anindya Bhattacharya
- LLC. Neuroscience Drug Discovery, Janssen Research & Development, 3210 Merryfield Row, San Diego, California
| | - Knut Biber
- Department of Psychiatry and Psychotherapy, University Hospital Freiburg, Hauptstrasse 5, Freiburg, Germany.,Department of Neuroscience, University Medical Center Groningen, University of Groningen, Ant. Deusinglaan 1, AV Groningen, The Netherlands
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43
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The effects of NONRATT021972 lncRNA siRNA on PC12 neuronal injury mediated by P2X7 receptor after exposure to oxygen-glucose deprivation. Purinergic Signal 2016; 12:479-87. [PMID: 27100355 DOI: 10.1007/s11302-016-9513-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 04/14/2016] [Indexed: 12/13/2022] Open
Abstract
Adenosine triphosphate (ATP) participates in signal transmission by acting on P2X receptors, and the P2X7 receptor is involved in the pathophysiological changes of ischemic injury. The PC12 cell line is a popular model system to study sympathetic neuronal function. Long noncoding RNAs (lncRNAs) are highly expressed in the nervous system and serve as regulatory RNAs. In this study, the effects of NONRATT021972 lncRNA siRNA on P2X7-mediated PC12 neuronal injury after exposure to oxygen-glucose deprivation (OGD) were investigated. Our results showed that the viability of PC12 cells cultured with OGD or the P2X7 agonist BzATP was significantly decreased. Treatment with NONRATT021972 siRNA reversed the decreased viability of PC12 cells under OGD conditions. The upregulated P2X7 mRNA and protein levels in PC12 cells under OGD conditions or BzATP treatment were significantly decreased when pretreated with NONRATT021972 siRNA. Moreover, NONRATT021972 siRNA treatment effectively suppressed the increase in [Ca(2+)]i induced by OGD or P2X7 agonists (ATP or BzATP) in PC12 cells. Therefore, treatment with NONRATT021972 siRNA may decrease sympathetic neuronal injury induced by ischemia.
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Ma Y, Wang J, Wang Y, Yang GY. The biphasic function of microglia in ischemic stroke. Prog Neurobiol 2016; 157:247-272. [PMID: 26851161 DOI: 10.1016/j.pneurobio.2016.01.005] [Citation(s) in RCA: 484] [Impact Index Per Article: 60.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 12/22/2015] [Accepted: 01/10/2016] [Indexed: 12/16/2022]
Abstract
Microglia are brain resident macrophages originated from primitive progenitor cells in the yolk sac. Microglia can be activated within hours and recruited to the lesion site. Traditionally, microglia activation is considered to play a deleterious role in ischemic stroke, as inhibition of microglia activation attenuates ischemia induced brain injury. However, increasing evidence show that microglia activation is critical for attenuating neuronal apoptosis, enhancing neurogenesis, and promoting functional recovery after cerebral ischemia. Differential polarization of microglia could likely explain the biphasic role of microglia in ischemia. We comprehensively reviewed the mechanisms involved in regulating microglia activation and polarization. The latest discoveries of microRNAs in modulating microglia function are discussed. In addition, the interaction between microglia and other cells including neurons, astrocytes, oligodendrocytes, and stem cells were also reviewed. Future therapies targeting microglia may not exclusively aim at suppressing microglia activation, but also at modulating microglia polarization at different stages of ischemic stroke. More work is needed to elucidate the cellular and molecular mechanisms of microglia polarization under ischemic environment. The roles of microRNAs and transplanted stem cells in mediating microglia activation and polarization during brain ischemia also need to be further studied.
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Affiliation(s)
- Yuanyuan Ma
- Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, China; Neuroscience and Neuroengineering Research Center, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Jixian Wang
- Neuroscience and Neuroengineering Research Center, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China; Department of Rehabilitation, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, China
| | - Yongting Wang
- Neuroscience and Neuroengineering Research Center, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China.
| | - Guo-Yuan Yang
- Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, China; Neuroscience and Neuroengineering Research Center, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China.
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45
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P2X7R large pore is partially blocked by pore forming proteins antagonists in astrocytes. J Bioenerg Biomembr 2016; 48:309-24. [DOI: 10.1007/s10863-016-9649-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 01/20/2016] [Indexed: 01/13/2023]
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46
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Pedata F, Dettori I, Coppi E, Melani A, Fusco I, Corradetti R, Pugliese AM. Purinergic signalling in brain ischemia. Neuropharmacology 2015; 104:105-30. [PMID: 26581499 DOI: 10.1016/j.neuropharm.2015.11.007] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 11/04/2015] [Accepted: 11/06/2015] [Indexed: 12/18/2022]
Abstract
Ischemia is a multifactorial pathology characterized by different events evolving in the time. After ischemia a primary damage due to the early massive increase of extracellular glutamate is followed by activation of resident immune cells, i.e microglia, and production or activation of inflammation mediators. Protracted neuroinflammation is now recognized as the predominant mechanism of secondary brain injury progression. Extracellular concentrations of ATP and adenosine in the brain increase dramatically during ischemia in concentrations able to stimulate their respective specific P2 and P1 receptors. Both ATP P2 and adenosine P1 receptor subtypes exert important roles in ischemia. Although adenosine exerts a clear neuroprotective effect through A1 receptors during ischemia, the use of selective A1 agonists is hampered by undesirable peripheral effects. Evidence up to now in literature indicate that A2A receptor antagonists provide protection centrally by reducing excitotoxicity, while agonists at A2A (and possibly also A2B) and A3 receptors provide protection by controlling massive infiltration and neuroinflammation in the hours and days after brain ischemia. Among P2X receptors most evidence indicate that P2X7 receptor contribute to the damage induced by the ischemic insult due to intracellular Ca(2+) loading in central cells and facilitation of glutamate release. Antagonism of P2X7 receptors might represent a new treatment to attenuate brain damage and to promote proliferation and maturation of brain immature resident cells that can promote tissue repair following cerebral ischemia. Among P2Y receptors, antagonists of P2Y12 receptors are of value because of their antiplatelet activity and possibly because of additional anti-inflammatory effects. Moreover strategies that modify adenosine or ATP concentrations at injury sites might be of value to limit damage after ischemia. This article is part of the Special Issue entitled 'Purines in Neurodegeneration and Neuroregeneration'.
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Affiliation(s)
- Felicita Pedata
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Viale Pieraccini, 6, 50139 Florence, Italy.
| | - Ilaria Dettori
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Viale Pieraccini, 6, 50139 Florence, Italy
| | - Elisabetta Coppi
- Department of Health Sciences, University of Florence, Viale Pieraccini, 6, 50139 Florence, Italy
| | - Alessia Melani
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Viale Pieraccini, 6, 50139 Florence, Italy
| | - Irene Fusco
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Viale Pieraccini, 6, 50139 Florence, Italy
| | - Renato Corradetti
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Viale Pieraccini, 6, 50139 Florence, Italy
| | - Anna Maria Pugliese
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Viale Pieraccini, 6, 50139 Florence, Italy
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Some Operational Characteristics of Glycine Release in Rat Retina: The Role of Reverse Mode Operation of Glycine Transporter Type-1 (GlyT-1) in Ischemic Conditions. Neurochem Res 2015; 41:73-85. [PMID: 26364050 DOI: 10.1007/s11064-015-1713-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 08/26/2015] [Accepted: 08/28/2015] [Indexed: 10/23/2022]
Abstract
Rat posterior eyecups containing the retina were prepared, loaded with [(3)H]glycine and superfused in order to determine its release originated from glycinergic amacrine cells and/or glial cells. Deprivation of oxygen and glucose from the Krebs-bicarbonate buffer used for superfusion evoked a marked increase of [(3)H]glycine release, an effect that was found to be external Ca(2+)-independent. Whereas oxygen and glucose deprivation increased [(3)H]glycine release, its uptake was reduced suggesting that energy deficiency shifts glycine transporter type-1 operation from normal to reverse mode. The increased release of [(3)H]glycine evoked by oxygen and glucose deprivation was suspended by addition of the non-competitive glycine transporter type-1 inhibitor NFPS and the competitive inhibitor ACPPB further suggesting the involvement of this transporter in the mediation of [(3)H]glycine release. Oxygen and glucose deprivation also evoked [(3)H]glutamate release from rat retina and the concomitantly occurring release of the NMDA receptor agonist glutamate and the coagonist glycine makes NMDA receptor pathological overstimulation possible in hypoxic conditions. [(3)H]Glutamate release was suspended by addition of the excitatory amino acid transporter inhibitor TBOA. Sarcosine, a substrate inhibitor of glycine transporter type-1, also increased [(3)H]glycine release probably by heteroexchange shifting transporter operation into reverse mode. This effect of sarcosine was also external Ca(2+)-independent and could be suspended by NFPS. Energy deficiency in retina induced by ouabain, an inhibitor of the Na(+)-K(+)-dependent ATPase, and by rotenone, a mitochondrial complex I inhibitor added with the glycolytic inhibitor 2-deoxy-D-glucose, led to increase of retinal [(3)H]glycine efflux. These effects of ouabain and rotenone/2-deoxy-D-glucose could also be blocked by NFPS pointed to the preferential reverse mode operation of glycine transporter type-1 as a consequence of impaired cellular energy homeostasis. Immunohistochemical studies revealed that glycine transporter type-1, of which reverse mode operation assures [(3)H]glycine release, is expressed in amacrine cells in the inner nuclear and plexiform layers of the retina and also in Müller macroglia cells. We conclude that disruption of the balanced normal/reverse mode operation of glycine transporter type-1 is likely a significant factor contributing to neurotoxic processes of the retina. The possibility to inhibit glycine transporter type-1 mediated glycine efflux by drugs more potently than glycine uptake might offer some therapeutic potential for the treatment of various neurodegenerative disorders of the retina.
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Wang W, Lu R, Feng DY, Liang LR, Liu B, Zhang H. Inhibition of microglial activation contributes to propofol-induced protection against post-cardiac arrest brain injury in rats. J Neurochem 2015; 134:892-903. [PMID: 26016627 DOI: 10.1111/jnc.13179] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 05/11/2015] [Accepted: 05/15/2015] [Indexed: 12/14/2022]
Abstract
It has been suggested that propofol can modulate microglial activity and hence may have potential roles against neuroinflammation following brain ischemic insult. However, whether and how propofol can inhibit post-cardiac arrest brain injury via inhibition of microglia activation remains unclear. A rat model of asphyxia cardiac arrest (CA) was created followed by cardiopulmonary resuscitation. CA induced marked microglial activation in the hippocampal CA1 region, revealed by increased OX42 and P2 class of purinoceptor 7 (P2X7R) expression, as well as p38 MAPK phosphorylation. Morris water maze showed that learning and memory deficits following CA could be inhibited or alleviated by pre-treatment with the microglial inhibitor minocycline or propofol. Microglial activation was significantly suppressed likely via the P2X7R/p-p38 pathway by propofol. Moreover, hippocampal neuronal injuries after CA were remarkably attenuated by propofol. In vitro experiment showed that propofol pre-treatment inhibited ATP-induced microglial activation and release of tumor necrosis factor-α and interleukin-1β. In addition, propofol protected neurons from injury when co-culturing with ATP-treated microglia. Our data suggest that propofol pre-treatment inhibits CA-induced microglial activation and neuronal injury in the hippocampus and ultimately improves cognitive function. We proposed a possible mechanism of propofol-mediated brain protection after cardiac arrest (CA). CA induces P2X7R upregulation and p38 phosphorylation in microglia, which induces release of TNF-α and IL-1β and consequent neuronal injury. Propofol could inhibit microglial activation and alleviate neuronal damage. Our results suggest propofol-induced anti-inflammatory treatment as a plausible strategy for therapeutic intervention in post-CA brain injury.
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Affiliation(s)
- Wei Wang
- State Key Laboratory of Military Stomatology, Department of Anesthesiology, School of Stomatology, the Fourth Military Medical University, Xi'an, China
| | - Rui Lu
- State Key Laboratory of Military Stomatology, Department of Anesthesiology, School of Stomatology, the Fourth Military Medical University, Xi'an, China
| | - Da-Yun Feng
- Department of Neurosurgery, Tangdu Hospital, the Fourth Military Medical University, Xi'an, China
| | - Li-Rong Liang
- State Key Laboratory of Military Stomatology, Department of Anesthesiology, School of Stomatology, the Fourth Military Medical University, Xi'an, China
| | - Bing Liu
- State Key Laboratory of Military Stomatology, Department of Anesthesiology, School of Stomatology, the Fourth Military Medical University, Xi'an, China
| | - Hui Zhang
- State Key Laboratory of Military Stomatology, Department of Anesthesiology, School of Stomatology, the Fourth Military Medical University, Xi'an, China
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Xia CY, Zhang S, Gao Y, Wang ZZ, Chen NH. Selective modulation of microglia polarization to M2 phenotype for stroke treatment. Int Immunopharmacol 2015; 25:377-82. [DOI: 10.1016/j.intimp.2015.02.019] [Citation(s) in RCA: 122] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 01/28/2015] [Accepted: 02/11/2015] [Indexed: 11/27/2022]
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Alves LA, de Melo Reis RA, de Souza CAM, de Freitas MS, Teixeira PCN, Neto Moreira Ferreira D, Xavier RF. The P2X7 receptor: Shifting from a low- to a high-conductance channel — An enigmatic phenomenon? BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:2578-87. [DOI: 10.1016/j.bbamem.2014.05.015] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 04/22/2014] [Accepted: 05/13/2014] [Indexed: 01/08/2023]
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