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Tachibana T, Notomi S, Funatsu J, Fujiwara K, Nakatake S, Murakami Y, Nakao S, Kanamoto T, Ikeda Y, Ishibashi T, Sonoda KH, Hisatomi T. Intraocular kinetics of pathological ATP after photoreceptor damage in rhegmatogenous retinal detachment. Jpn J Ophthalmol 2024:10.1007/s10384-024-01087-x. [PMID: 39060674 DOI: 10.1007/s10384-024-01087-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 05/29/2024] [Indexed: 07/28/2024]
Abstract
PURPOSE Extracellular Adenosine triphosphate (ATP) released by dying cells may cause a secondary cell death in neighboring cells in retinal degeneration. We investigated intraocular ATP kinetics to gain mechanical insights into the pathology in rhegmatogenous retinal detachment (RRD). STUDY DESIGN Retrospective clinical study. METHODS Vitreous or subretinal fluids (SRF) were obtained from patients with RRD (n=75), macular hole (MH; n=20), and epiretinal membrane (ERM; n=35) during vitrectomy. ATP levels in those samples were measured by luciferase assay. RESULTS Mean ATP levels in the vitreous from RRD patients were significantly higher compared to those from MH and ERM patients (2.3 and 0.3 nM, respectively. P<0.01). Mean ATP levels in the SRF from RRD (11.7 nM) were higher than those in the vitreous from RRD (P<0.01). Mean ATP levels in the vitreous with short durations (1-8 days) of RRD were higher compared to those with long durations (>8 days) (3.2 and 1.4 nM, respectively. P<0.05). Similarly, ATP in SRF with short durations were higher than those with long durations (23.8 and 3.6 nM, respectively. P<0.05). Furthermore, the concentrations of ectonucleoside triphosphate diphosphohydrolase-1 (ENTPD1), a major ATP degradative enzyme, in the vitreous from RRD were higher than those from MH/ERM (1.2 and 0.2 ng/ml, respectively. P<0.01). ENTPD1 expression was localized in the cytoplasm of CD11b-positive infiltrating cells in the vitreous and retinal cells. CONCLUSION ATP increased in the vitreous and SRF in RRD and decreased over time with an upregulation of ENTPD1. The kinetics indicate the pathological mechanism of the excessive extracellular ATP after RRD.
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Affiliation(s)
- Takashi Tachibana
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
- Ohshima Eye Hospital, Fukuoka, Japan
| | - Shoji Notomi
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Jun Funatsu
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Kohta Fujiwara
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Shunji Nakatake
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yusuke Murakami
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Shintaro Nakao
- Department of Ophthalmology, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | | | - Yasuhiro Ikeda
- Department of Ophthalmology, Faculty of Medicine, Miyazaki University, Miyazaki, Japan
| | - Tatsuro Ishibashi
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Koh-Hei Sonoda
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Toshio Hisatomi
- Department of Ophthalmology, Fukuoka University Chikushi Hospital, 1-1-1 Zokumyouin, Chikushino, Fukuoka, 818-8502, Japan.
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2
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Alarcon-Martinez L, Shiga Y, Villafranca-Baughman D, Cueva Vargas JL, Vidal Paredes IA, Quintero H, Fortune B, Danesh-Meyer H, Di Polo A. Neurovascular dysfunction in glaucoma. Prog Retin Eye Res 2023; 97:101217. [PMID: 37778617 DOI: 10.1016/j.preteyeres.2023.101217] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/23/2023] [Accepted: 09/25/2023] [Indexed: 10/03/2023]
Abstract
Retinal ganglion cells, the neurons that die in glaucoma, are endowed with a high metabolism requiring optimal provision of oxygen and nutrients to sustain their activity. The timely regulation of blood flow is, therefore, essential to supply firing neurons in active areas with the oxygen and glucose they need for energy. Many glaucoma patients suffer from vascular deficits including reduced blood flow, impaired autoregulation, neurovascular coupling dysfunction, and blood-retina/brain-barrier breakdown. These processes are tightly regulated by a community of cells known as the neurovascular unit comprising neurons, endothelial cells, pericytes, Müller cells, astrocytes, and microglia. In this review, the neurovascular unit takes center stage as we examine the ability of its members to regulate neurovascular interactions and how their function might be altered during glaucomatous stress. Pericytes receive special attention based on recent data demonstrating their key role in the regulation of neurovascular coupling in physiological and pathological conditions. Of particular interest is the discovery and characterization of tunneling nanotubes, thin actin-based conduits that connect distal pericytes, which play essential roles in the complex spatial and temporal distribution of blood within the retinal capillary network. We discuss cellular and molecular mechanisms of neurovascular interactions and their pathophysiological implications, while highlighting opportunities to develop strategies for vascular protection and regeneration to improve functional outcomes in glaucoma.
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Affiliation(s)
- Luis Alarcon-Martinez
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada; Centre for Eye Research Australia, University of Melbourne, Melbourne, Australia
| | - Yukihiro Shiga
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada
| | - Deborah Villafranca-Baughman
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada
| | - Jorge L Cueva Vargas
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada
| | - Isaac A Vidal Paredes
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada
| | - Heberto Quintero
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada
| | - Brad Fortune
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Healthy, Portland, OR, USA
| | - Helen Danesh-Meyer
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, New Zealand
| | - Adriana Di Polo
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada.
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3
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Maggi MA, Consonni R, Cagliani LR, Prestipino G, Bisti S, Picco C. Saffron and retinal neurodegenerative diseases: Relevance of chemical composition. J Anat 2023; 243:265-273. [PMID: 35778985 PMCID: PMC10335369 DOI: 10.1111/joa.13722] [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: 01/17/2022] [Revised: 05/19/2022] [Accepted: 06/15/2022] [Indexed: 11/29/2022] Open
Abstract
Saffron is an ancient spice largely used in traditional medicine. It has been found to be effective in treatment of retinal neurodegenerative diseases like age-related macular degeneration and Stargardt. In the present manuscript, it is shown that saffron's neuroprotective power is strongly related to the bioactivity of all its chemical components. Nuclear magnetic resonance spectroscopy and "in vitro" experiments confirm the relevance of crocins for saffron efficacy. These results underline the importance of strictly defining the chemical composition of the natural compounds in saffron to optimize their effectiveness in the treatment of diseases.
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Affiliation(s)
- Maria A. Maggi
- Hortus Novus srlCanistroItaly
- Department of Physical and Chemical SciencesUniversity of L’AquilaCoppitoItaly
| | - Roberto Consonni
- Lab. NMR, Institute of Chemical Sciences and Technologies “G. Natta” (SCITEC)National Research CouncilMilanItaly
- National Institute of Biostructure and Biosystem (INBB)RomeItaly
| | - Laura R. Cagliani
- Lab. NMR, Institute of Chemical Sciences and Technologies “G. Natta” (SCITEC)National Research CouncilMilanItaly
| | | | - Silvia Bisti
- National Institute of Biostructure and Biosystem (INBB)RomeItaly
- Department of Biotecnology and Applied Clinical Sciences, DISCABUniversity of L’AquilaCoppitoItaly
| | - Cristiana Picco
- National Institute of Biostructure and Biosystem (INBB)RomeItaly
- Institute of Biophysics (IBF)National Research CouncilGenoaItaly
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4
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Shinozaki Y, Saito K, Kashiwagi K, Koizumi S. Ocular P2 receptors and glaucoma. Neuropharmacology 2023; 222:109302. [PMID: 36341810 DOI: 10.1016/j.neuropharm.2022.109302] [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: 07/08/2022] [Revised: 10/08/2022] [Accepted: 10/21/2022] [Indexed: 11/06/2022]
Abstract
Adenosine triphosphate (ATP), an energy source currency in cells, is released or leaked to the extracellular space under both physiological and pathological conditions. Extracellular ATP functions as an intercellular signaling molecule through activation of purinergic P2 receptors. Ocular tissue and cells release ATP in response to physiological stimuli such as intraocular pressure (IOP), and P2 receptor activation regulates IOP elevation or reduction. Dysregulated purinergic signaling may cause abnormally elevated IOP, which is one of the major risk factors for glaucoma. Glaucoma, a leading cause of blindness worldwide, is characterized by progressive degeneration of optic nerves and retinal ganglion cells (RGCs), which are essential retinal neurons that transduce visual information to the brain. An elevation in IOP may stress RGCs and increase the risk for glaucoma pathogenesis. In the aqueous humor of human patients with glaucoma, the ATP level is significantly elevated. Such excess amount of ATP may directly cause RGC death via a specific subtype of P2 receptors. Dysregulated purinergic signaling may also trigger inflammation, oxidative stress, and excitotoxicity via activating non-neuronal cell types such as glial cells. In this review, we discussed the physiological roles of extracellular nucleotides in the ocular tissue and their potential role in the pathogenesis of glaucoma. This article is part of the Special Issue on 'Purinergic Signaling: 50 years'.
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Affiliation(s)
- Youichi Shinozaki
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan; Interdisciplinary Brain-Immune Research Center, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Kozo Saito
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Kenji Kashiwagi
- Department of Ophthalmology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Schuichi Koizumi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan; Interdisciplinary Brain-Immune Research Center, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan.
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5
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Martínez-Gil N, Kutsyr O, Noailles A, Fernández-Sánchez L, Vidal L, Sánchez-Sáez X, Sánchez-Castillo C, Lax P, Cuenca N, García AG, Maneu V. Purinergic Receptors P2X7 and P2X4 as Markers of Disease Progression in the rd10 Mouse Model of Inherited Retinal Dystrophy. Int J Mol Sci 2022; 23:ijms232314758. [PMID: 36499084 PMCID: PMC9739106 DOI: 10.3390/ijms232314758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 11/18/2022] [Accepted: 11/21/2022] [Indexed: 11/29/2022] Open
Abstract
The purinergic receptor P2X7 (P2X7R) is implicated in all neurodegenerative diseases of the central nervous system. It is also involved in the retinal degeneration associated with glaucoma, age-related macular degeneration, and diabetic retinopathy, and its overexpression in the retina is evident in these disorders. Retinitis pigmentosa is a progressive degenerative disease that ultimately leads to blindness. Here, we investigated the expression of P2X7R during disease progression in the rd10 mouse model of RP. As the purinergic receptor P2X4 is widely co-expressed with P2X7R, we also studied its expression in the retina of rd10 mice. The expression of P2X7R and P2X4R was examined by immunohistochemistry, flow cytometry, and western blotting. In addition, we analyzed retinal functionality by electroretinographic recordings of visual responses and optomotor tests and retinal morphology. We found that the expression of P2X7R and P2X4R increased in rd10 mice concomitant with disease progression, but with different cellular localization. Our findings suggest that P2X7R and P2X4R might play an important role in RP progression, which should be further analyzed for the pharmacological treatment of inherited retinal dystrophies.
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Affiliation(s)
- Natalia Martínez-Gil
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, 03690 Alicante, Spain
| | - Oksana Kutsyr
- Departamento de Óptica, Farmacología y Anatomía, Universidad de Alicante, 03690 Alicante, Spain
| | - Agustina Noailles
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, 03690 Alicante, Spain
| | - Laura Fernández-Sánchez
- Departamento de Óptica, Farmacología y Anatomía, Universidad de Alicante, 03690 Alicante, Spain
| | - Lorena Vidal
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, 03690 Alicante, Spain
| | - Xavier Sánchez-Sáez
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, 03690 Alicante, Spain
| | - Carla Sánchez-Castillo
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, 03690 Alicante, Spain
| | - Pedro Lax
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, 03690 Alicante, Spain
| | - Nicolás Cuenca
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, 03690 Alicante, Spain
| | - Antonio G. García
- Departamento de Farmacología y Terapéutica, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, 28029 Madrid, Spain
- Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa, 28006 Madrid, Spain
| | - Victoria Maneu
- Departamento de Óptica, Farmacología y Anatomía, Universidad de Alicante, 03690 Alicante, Spain
- Correspondence:
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6
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Pinilla I, Maneu V, Campello L, Fernández-Sánchez L, Martínez-Gil N, Kutsyr O, Sánchez-Sáez X, Sánchez-Castillo C, Lax P, Cuenca N. Inherited Retinal Dystrophies: Role of Oxidative Stress and Inflammation in Their Physiopathology and Therapeutic Implications. Antioxidants (Basel) 2022; 11:antiox11061086. [PMID: 35739983 PMCID: PMC9219848 DOI: 10.3390/antiox11061086] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 05/24/2022] [Accepted: 05/26/2022] [Indexed: 12/13/2022] Open
Abstract
Inherited retinal dystrophies (IRDs) are a large group of genetically and clinically heterogeneous diseases characterized by the progressive degeneration of the retina, ultimately leading to loss of visual function. Oxidative stress and inflammation play fundamental roles in the physiopathology of these diseases. Photoreceptor cell death induces an inflammatory state in the retina. The activation of several molecular pathways triggers different cellular responses to injury, including the activation of microglia to eliminate debris and recruit inflammatory cells from circulation. Therapeutical options for IRDs are currently limited, although a small number of patients have been successfully treated by gene therapy. Many other therapeutic strategies are being pursued to mitigate the deleterious effects of IRDs associated with oxidative metabolism and/or inflammation, including inhibiting reactive oxygen species’ accumulation and inflammatory responses, and blocking autophagy. Several compounds are being tested in clinical trials, generating great expectations for their implementation. The present review discusses the main death mechanisms that occur in IRDs and the latest therapies that are under investigation.
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Affiliation(s)
- Isabel Pinilla
- Aragón Health Research Institute (IIS Aragón), 50009 Zaragoza, Spain
- Department of Ophthalmology, Lozano Blesa, University Hospital, 50009 Zaragoza, Spain
- Department of Surgery, University of Zaragoza, 50009 Zaragoza, Spain
- Correspondence: (I.P.); (V.M.)
| | - Victoria Maneu
- Department of Optics, Pharmacology and Anatomy, University of Alicante, 03690 Alicante, Spain;
- Alicante Institute for Health and Biomedical Research (ISABIAL), 03010 Alicante, Spain; (P.L.); (N.C.)
- Correspondence: (I.P.); (V.M.)
| | - Laura Campello
- Department of Physiology, Genetics and Microbiology, University of Alicante, 03690 Alicante, Spain; (L.C.); (N.M.-G.); (O.K.); (X.S.-S.); (C.S.-C.)
| | - Laura Fernández-Sánchez
- Department of Optics, Pharmacology and Anatomy, University of Alicante, 03690 Alicante, Spain;
| | - Natalia Martínez-Gil
- Department of Physiology, Genetics and Microbiology, University of Alicante, 03690 Alicante, Spain; (L.C.); (N.M.-G.); (O.K.); (X.S.-S.); (C.S.-C.)
| | - Oksana Kutsyr
- Department of Physiology, Genetics and Microbiology, University of Alicante, 03690 Alicante, Spain; (L.C.); (N.M.-G.); (O.K.); (X.S.-S.); (C.S.-C.)
| | - Xavier Sánchez-Sáez
- Department of Physiology, Genetics and Microbiology, University of Alicante, 03690 Alicante, Spain; (L.C.); (N.M.-G.); (O.K.); (X.S.-S.); (C.S.-C.)
| | - Carla Sánchez-Castillo
- Department of Physiology, Genetics and Microbiology, University of Alicante, 03690 Alicante, Spain; (L.C.); (N.M.-G.); (O.K.); (X.S.-S.); (C.S.-C.)
| | - Pedro Lax
- Alicante Institute for Health and Biomedical Research (ISABIAL), 03010 Alicante, Spain; (P.L.); (N.C.)
- Department of Physiology, Genetics and Microbiology, University of Alicante, 03690 Alicante, Spain; (L.C.); (N.M.-G.); (O.K.); (X.S.-S.); (C.S.-C.)
| | - Nicolás Cuenca
- Alicante Institute for Health and Biomedical Research (ISABIAL), 03010 Alicante, Spain; (P.L.); (N.C.)
- Department of Physiology, Genetics and Microbiology, University of Alicante, 03690 Alicante, Spain; (L.C.); (N.M.-G.); (O.K.); (X.S.-S.); (C.S.-C.)
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7
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Combined drug triads for synergic neuroprotection in retinal degeneration. Biomed Pharmacother 2022; 149:112911. [DOI: 10.1016/j.biopha.2022.112911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 03/28/2022] [Accepted: 03/29/2022] [Indexed: 11/23/2022] Open
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8
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Markitantova YV, Simirskii VN. The Role of the Purinergic Signaling System in the Control of Histogenesis, Homeostasis, and Pathogenesis of the Vertebrate Retina. Russ J Dev Biol 2021. [DOI: 10.1134/s1062360421060084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Brandli A, Dudczig S, Currie PD, Jusuf PR. Photoreceptor ablation following ATP induced injury triggers Müller glia driven regeneration in zebrafish. Exp Eye Res 2021; 207:108569. [PMID: 33839111 DOI: 10.1016/j.exer.2021.108569] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 03/31/2021] [Accepted: 04/01/2021] [Indexed: 11/29/2022]
Abstract
Retinal regeneration research offers hope to people affected by visual impairment due to disease and injury. Ongoing research has explored many avenues towards retinal regeneration, including those that utilizes implantation of devices, cells or targeted viral-mediated gene therapy. These results have so far been limited, as gene therapy only has applications for rare single-gene mutations and implantations are invasive and in the case of cell transplantation donor cells often fail to integrate with adult neurons. An alternative mode of retinal regeneration utilizes a stem cell population unique to vertebrate retina - Müller glia (MG). Endogenous MG can readily regenerate lost neurons spontaneously in zebrafish and to a very limited extent in mammalian retina. The use of adenosine triphosphate (ATP) has been shown to induce retinal degeneration and activation of the MG in mammals, but whether this is conserved to other vertebrate species including those with higher regenerative capacity remains unknown. In our study, we injected a single dose of ATP intravitreal in zebrafish to characterize the cell death and MG induced regeneration. We used TUNEL labelling on retinal sections to show that ATP caused localised death of photoreceptors and ganglion cells within 24 h. Histology of GFP-transgenic zebrafish and BrdU injected fish demonstrated that MG proliferation peaked at days 3 and 4 post-ATP injection. Using BrdU labelling and photoreceptor markers (Zpr1) we observed regeneration of lost rod photoreceptors at day 14. This study has been undertaken to allow for comparative studies between mammals and zebrafish that use the same specific induction method of injury, i.e. ATP induced injury to allow for direct comparison of across species to narrow down resulting differences that might reflect the differing regenerative capacity. The ultimate aim of this work is to recapitulate pro-neurogenesis Müller glia signaling in mammals to produce new neurons that integrate with the existing retinal circuit to restore vision.
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Affiliation(s)
- Alice Brandli
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, 3800, Australia; Deptartment of Anatomy and Neuroscience, University of Melbourne, Parkville, VIC, 3010, Australia.
| | - Stefanie Dudczig
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, 3800, Australia; School of BioSciences, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Peter D Currie
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Patricia R Jusuf
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, 3800, Australia; School of BioSciences, University of Melbourne, Parkville, VIC, 3010, Australia.
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10
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Retinal ganglion cell dysfunction in mice following acute intraocular pressure is exacerbated by P2X7 receptor knockout. Sci Rep 2021; 11:4184. [PMID: 33603067 PMCID: PMC7893065 DOI: 10.1038/s41598-021-83669-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 12/22/2020] [Indexed: 12/21/2022] Open
Abstract
There is increasing evidence for the vulnerability of specific retinal ganglion cell (RGC) types in those with glaucoma and in animal models. In addition, the P2X7-receptor (P2X7-R) has been suggested to contribute to RGC death following stimulation and elevated IOP, though its role in RGC dysfunction prior to death has not been examined. Therefore, we examined the effect of an acute, non-ischemic intraocular pressure (IOP) insult (50 mmHg for 30 min) on RGC function in wildtype mice and P2X7-R knockout (P2X7-KO) mice. We examined retinal function using electroretinogram recordings and individual RGC responses using multielectrode arrays, 3 days following acute IOP elevation. Immunohistochemistry was used to examine RGC cell death and P2X7-R expression in several RGC types. Acute intraocular pressure elevation produced pronounced dysfunction in RGCs; whilst other retinal neuronal responses showed lesser changes. Dysfunction at 3 days post-injury was not associated with RGC loss or changes in receptive field size. However, in wildtype animals, OFF-RGCs showed reduced spontaneous and light-elicited activity. In the P2X7-KO, both ON- and OFF-RGC light-elicited responses were reduced. Expression of P2X7-R in wildtype ON-RGC dendrites was higher than in other RGC types. In conclusion, OFF-RGCs were vulnerable to acute IOP elevation and their dysfunction was not rescued by genetic ablation of P2X7-R. Indeed, knockout of P2X7-R also caused ON-RGC dysfunction. These findings aid our understanding of how pressure affects RGC function and suggest treatments targeting the P2X7-R need to be carefully considered.
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Greferath U, Huynh M, Jobling AI, Vessey KA, Venables G, Surrao D, O'Neill HC, Limnios IJ, Fletcher EL. Dorsal-Ventral Differences in Retinal Structure in the Pigmented Royal College of Surgeons Model of Retinal Degeneration. Front Cell Neurosci 2021; 14:553708. [PMID: 33536874 PMCID: PMC7848141 DOI: 10.3389/fncel.2020.553708] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 12/17/2020] [Indexed: 11/29/2022] Open
Abstract
Retinitis pigmentosa is a family of inherited retinal degenerations associated with gradual loss of photoreceptors, that ultimately leads to irreversible vision loss. The Royal College of Surgeon's (RCS) rat carries a recessive mutation affecting mer proto-oncogene tyrosine kinase (merTK), that models autosomal recessive disease. The aim of this study was to understand the glial, microglial, and photoreceptor changes that occur in different retinal locations with advancing disease. Pigmented RCS rats (RCS-p+/LAV) and age-matched isogenic control rdy (RCS-rdy +p+/LAV) rats aged postnatal day 18 to 6 months were evaluated for in vivo retinal structure and function using optical coherence tomography and electroretinography. Retinal tissues were assessed using high resolution immunohistochemistry to evaluate changes in photoreceptors, glia and microglia in the dorsal, and ventral retina. Photoreceptor dysfunction and death occurred from 1 month of age. There was a striking difference in loss of photoreceptors between the dorsal and ventral retina, with a greater number of photoreceptors surviving in the dorsal retina, despite being adjacent a layer of photoreceptor debris within the subretinal space. Loss of photoreceptors in the ventral retina was associated with fragmentation of the outer limiting membrane, extension of glial processes into the subretinal space that was accompanied by possible adhesion and migration of mononuclear phagocytes in the subretinal space. Overall, these findings highlight that breakdown of the outer limiting membrane could play an important role in exacerbating photoreceptor loss in the ventral retina. Our results also highlight the value of using the RCS rat to model sectorial retinitis pigmentosa, a disease known to predominantly effect the inferior retina.
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Affiliation(s)
- Una Greferath
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, Australia
| | - Mario Huynh
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, Australia
| | - Andrew Ian Jobling
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, Australia
| | - Kirstan Anne Vessey
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, Australia
| | - Gene Venables
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, Australia
| | - Denver Surrao
- Clem Jones Centre for Regenerative Medicine, Faculty of Health Sciences and Medicine, Bond University, Gold Coast, QLD, Australia
| | - Helen Christine O'Neill
- Clem Jones Centre for Regenerative Medicine, Faculty of Health Sciences and Medicine, Bond University, Gold Coast, QLD, Australia
| | - Ioannis J Limnios
- Clem Jones Centre for Regenerative Medicine, Faculty of Health Sciences and Medicine, Bond University, Gold Coast, QLD, Australia
| | - Erica Lucy Fletcher
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, Australia
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12
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Fletcher EL. Advances in understanding the mechanisms of retinal degenerations. Clin Exp Optom 2020; 103:723-732. [PMID: 33090561 DOI: 10.1111/cxo.13146] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 08/21/2020] [Accepted: 08/23/2020] [Indexed: 01/13/2023] Open
Abstract
Photoreceptor death is an important contributor to irreversible vision loss worldwide. In this review, I outline our work examining the role that purines, such as adenosine triphosphate (ATP), have in normal retinal function and in retinal disease. Our work shows that the actions of ATP, mediated by P2X receptors, are expressed in various retinal layers including photoreceptor terminals, and when stimulated by excessive levels of ATP is associated with rapid death of neurons. Treatment with a compound that blocks the action of P2X and some P2Y receptors reduces photoreceptor death in a mouse model of retinal degeneration. Our observations not only provide a means for developing a potential treatment for reducing photoreceptor death, but also provides a novel way of studying the neural plasticity effects that develop in the inner retina following photoreceptor death. There are a range of inner retinal changes that could influence the effectiveness of retinal prostheses. Indeed, using an ATP-induced degeneration model, we established that the amount of electrical stimulation required to elicit a response in the visual cortex was affected by the level of glial scarring. However, changes in P2X7 receptor expression by OFF ganglion cells during retinal degeneration can also be exploited by photoswitches to restore light sensitivity to degenerated retinae. Finally, our work has also considered how P2X7 expression by innate immune cells, and its role as a scavenger receptor, contributes to age-related macular degeneration (AMD). Our results show that loss of P2X7 function is associated with thickening of Bruch's membrane as well as increased risk of advanced disease in people with AMD. Overall, our work over the last 20 years highlights the importance of purinergic signalling in normal retinal function and retinal disease and suggest that developing therapies that target P2X7 function could be of benefit for these diseases.
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Affiliation(s)
- Erica L Fletcher
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia
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13
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Romano GL, Amato R, Lazzara F, Porciatti V, Chou TH, Drago F, Bucolo C. P2X7 receptor antagonism preserves retinal ganglion cells in glaucomatous mice. Biochem Pharmacol 2020; 180:114199. [PMID: 32798466 DOI: 10.1016/j.bcp.2020.114199] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 07/29/2020] [Accepted: 08/11/2020] [Indexed: 02/07/2023]
Abstract
To investigate the role of P2X7 receptor to preserve retinal ganglion cells (RGCs) structure and function in a genetic mouse model (DBA/2J mouse) of age-related glaucomatous neurodegeneration. Chronic treatment with P2X7 receptor antagonist eye drops was carried out in order to assess RGCs function and density by pattern electroretinogram (PERG) and RBPMS immunostaining, respectively. Further, microglia activation was assessed in flat-mounted retina by using Iba-1 immunostaining. Untreated glaucomatous eyes displayed significant microglia activation, alteration of PERG signal, and RGCs loss. In the P2X7 receptor antagonist-treated eyes, the PERG signal was significantly (p < 0.05) improved compared to controls, along with a significant (p < 0.05) reduction in terms of retinal microglial activation, and remarkable preservation of RGCs density. Altogether, these findings demonstrated that topical treatment with a P2X7 receptor antagonist has a neuroprotective effect on RGCs in glaucomatous mice, suggesting an appealing pharmacological approach to prevent retinal degenerative damage in optic neuropathy.
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Affiliation(s)
- Giovanni Luca Romano
- Biomedical and Biotechnological Sciences Department, University of Catania, Catania, Italy; Bascom Palmer Eye Institute, University of Miami, Miller School of Medicine, Miami, FL, United States
| | - Rosario Amato
- Bascom Palmer Eye Institute, University of Miami, Miller School of Medicine, Miami, FL, United States; Department of Biology, University of Pisa, Pisa, Italy
| | - Francesca Lazzara
- Biomedical and Biotechnological Sciences Department, University of Catania, Catania, Italy; Bascom Palmer Eye Institute, University of Miami, Miller School of Medicine, Miami, FL, United States
| | - Vittorio Porciatti
- Bascom Palmer Eye Institute, University of Miami, Miller School of Medicine, Miami, FL, United States
| | - Tsung-Han Chou
- Bascom Palmer Eye Institute, University of Miami, Miller School of Medicine, Miami, FL, United States
| | - Filippo Drago
- Biomedical and Biotechnological Sciences Department, University of Catania, Catania, Italy; Center for Research in Ocular Pharmacology - CERFO, University of Catania, Catania, Italy
| | - Claudio Bucolo
- Biomedical and Biotechnological Sciences Department, University of Catania, Catania, Italy; Center for Research in Ocular Pharmacology - CERFO, University of Catania, Catania, Italy
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14
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Calzaferri F, Ruiz-Ruiz C, de Diego AMG, de Pascual R, Méndez-López I, Cano-Abad MF, Maneu V, de Los Ríos C, Gandía L, García AG. The purinergic P2X7 receptor as a potential drug target to combat neuroinflammation in neurodegenerative diseases. Med Res Rev 2020; 40:2427-2465. [PMID: 32677086 DOI: 10.1002/med.21710] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 06/22/2020] [Accepted: 06/27/2020] [Indexed: 12/25/2022]
Abstract
Neurodegenerative diseases (NDDs) represent a huge social burden, particularly in Alzheimer's disease (AD) in which all proposed treatments investigated in murine models have failed during clinical trials (CTs). Thus, novel therapeutic strategies remain crucial. Neuroinflammation is a common pathogenic feature of NDDs. As purinergic P2X7 receptors (P2X7Rs) are gatekeepers of inflammation, they could be developed as drug targets for NDDs. Herein, we review this challenging hypothesis and comment on the numerous studies that have investigated P2X7Rs, emphasizing their molecular structure and functions, as well as their role in inflammation. Then, we elaborate on research undertaken in the field of medicinal chemistry to determine potential P2X7R antagonists. Subsequently, we review the state of neuroinflammation and P2X7R expression in the brain, in animal models and patients suffering from AD, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease, multiple sclerosis, and retinal degeneration. Next, we summarize the in vivo studies testing the hypothesis that by mitigating neuroinflammation, P2X7R blockers afford neuroprotection, increasing neuroplasticity and neuronal repair in animal models of NDDs. Finally, we reviewed previous and ongoing CTs investigating compounds directed toward targets associated with NDDs; we propose that CTs with P2X7R antagonists should be initiated. Despite the high expectations for putative P2X7Rs antagonists in various central nervous system diseases, the field is moving forward at a relatively slow pace, presumably due to the complexity of P2X7Rs. A better pharmacological approach to combat NDDs would be a dual strategy, combining P2X7R antagonism with drugs targeting a selective pathway in a given NDD.
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Affiliation(s)
- Francesco Calzaferri
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Cristina Ruiz-Ruiz
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Antonio M G de Diego
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria, Hospital Universitario de La Princesa, Universidad Autónoma de Madrid, Madrid, Spain
| | - Ricardo de Pascual
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Iago Méndez-López
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - María F Cano-Abad
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria, Hospital Universitario de La Princesa, Universidad Autónoma de Madrid, Madrid, Spain
| | - Victoria Maneu
- Departamento de Óptica, Farmacología y Anatomía, Universidad de Alicante, San Vicente del Raspeig, Spain
| | - Cristóbal de Los Ríos
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria, Hospital Universitario de La Princesa, Universidad Autónoma de Madrid, Madrid, Spain
| | - Luis Gandía
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Antonio G García
- Departamento de Farmacología, Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria, Hospital Universitario de La Princesa, Universidad Autónoma de Madrid, Madrid, Spain
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15
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The Role of Purinergic Receptors in the Circadian System. Int J Mol Sci 2020; 21:ijms21103423. [PMID: 32408622 PMCID: PMC7279285 DOI: 10.3390/ijms21103423] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/30/2020] [Accepted: 05/06/2020] [Indexed: 12/24/2022] Open
Abstract
The circadian system is an internal time-keeping system that synchronizes the behavior and physiology of an organism to the 24 h solar day. The master circadian clock, the suprachiasmatic nucleus (SCN), resides in the hypothalamus. It receives information about the environmental light/dark conditions through the eyes and orchestrates peripheral oscillators. Purinergic signaling is mediated by extracellular purines and pyrimidines that bind to purinergic receptors and regulate multiple body functions. In this review, we highlight the interaction between the circadian system and purinergic signaling to provide a better understanding of rhythmic body functions under physiological and pathological conditions.
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16
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Comparison of mRNA Expression of P2X Receptor Subtypes in Different Arterial Tissues of Rats. Biochem Genet 2020; 58:677-690. [PMID: 32385670 DOI: 10.1007/s10528-020-09968-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 04/24/2020] [Indexed: 10/24/2022]
Abstract
This study aims to compare the expression of P2X receptor subtype mRNA in different arterial tissues of rats. After the rats were sacrificed, the internal carotid, pulmonary, thoracic aorta, mesenteric and caudal arteries were dissected out. Then, the P2X receptor mRNA expression in different blood vessels was detected by reverse transcription-polymerase chain reaction (RT-PCR) and real-time quantitative polymerase chain reaction. The P2X1, P2X4 and P2X7 receptor mRNA amplification products revealed specific bands of the same size as the amplified target fragment in their respective lanes, while the P2X2, P2X3, P2X5 and P2X6 receptor mRNA amplification products did not reveal significant specific bands in their respective lanes by RT-PCR. Based on the P2X1 receptor mRNA expression of the mesenteric artery, there were no significant differences in the internal carotid, pulmonary and thoracic aorta (0.64 ± 0.07, 0.17 ± 0.11 and 1.49 ± 0.65, respectively). However, the P2X1 receptor mRNA expression level in the caudal artery significantly increased (11.06 ± 1.99, P < 0.01). Furthermore, there was no difference in P2X4 receptor mRNA expression among these five blood vessels (P > 0.05). The P2X7 receptor mRNA expression level was significantly different: pulmonary artery < tail artery = thoracic aorta < internal carotid artery < mesenteric artery. The relative P2X1 receptor mRNA expression in the caudal artery was observed to be elevated when compared to that of the internal carotid, pulmonary and thoracic aorta as well as the mesenteric arteries. The P2X7 receptor mRNA expression level is pulmonary artery < caudal artery = thoracic aorta < internal carotid artery < mesenteric artery. P2X4 receptor mRNA expression was not significantly different among these five blood vessels.
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17
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Glaucoma: A Degenerative Optic Neuropathy Related to Neuroinflammation? Cells 2020; 9:cells9030535. [PMID: 32106630 PMCID: PMC7140467 DOI: 10.3390/cells9030535] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/20/2020] [Accepted: 02/21/2020] [Indexed: 12/20/2022] Open
Abstract
Glaucoma is one of the leading causes of irreversible blindness in the world and remains a major public health problem. To date, incomplete knowledge of this disease’s pathophysiology has resulted in current therapies (pharmaceutical or surgical) unfortunately having only a slowing effect on disease progression. Recent research suggests that glaucomatous optic neuropathy is a disease that shares common neuroinflammatory mechanisms with “classical” neurodegenerative pathologies. In addition to the death of retinal ganglion cells (RGCs), neuroinflammation appears to be a key element in the progression and spread of this disease. Indeed, early reactivity of glial cells has been observed in the retina, but also in the central visual pathways of glaucoma patients and in preclinical models of ocular hypertension. Moreover, neuronal lesions are not limited to retinal structure, but also occur in central visual pathways. This review summarizes and puts into perspective the experimental and clinical data obtained to date to highlight the need to develop neuroprotective and immunomodulatory therapies to prevent blindness in glaucoma patients.
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18
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Medrano MP, Pisera-Fuster A, Bernabeu RO, Faillace MP. P2X7 and A 2A receptor endogenous activation protects against neuronal death caused by CoCl 2 -induced photoreceptor toxicity in the zebrafish retina. J Comp Neurol 2020; 528:2000-2020. [PMID: 31997350 DOI: 10.1002/cne.24869] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 01/09/2020] [Accepted: 01/22/2020] [Indexed: 12/20/2022]
Abstract
Injured retinas in mammals do not regenerate and heal with loss of function. The adult retina of zebrafish self-repairs after damage by activating cell-intrinsic mechanisms, which are regulated by extrinsic signal interactions. Among relevant regulatory extrinsic systems, purinergic signaling regulates progenitor proliferation during retinogenesis and regeneration and glia proliferation in proliferative retinopathies. ATP-activated P2X7 (P2RX7) and adenosine (P1R) receptors are involved in the progression of almost all retinopathies leading to blindness. Here, we examined P2RX7 and P1R participation in the retina regenerative response induced by photoreceptor damage caused by a specific dose of CoCl2 . First, we found that treatment of uninjured retinas with a potent agonist of P2RX7 (BzATP) provoked photoreceptor damage and mitotic activation of multipotent progenitors. In CoCl2 -injured retinas, blockade of endogenous extracellular ATP activity on P2RX7 caused further neurodegeneration, Müller cell gliosis, progenitor proliferation, and microglia reactivity. P2RX7 inhibition in injured retinas also increased the expression of lin28a and tnfα genes, which are related to multipotent progenitor proliferation. Levels of hif1α, vegf3r, and vegfaa mRNA were enhanced by blockade of P2RX7 immediately after injury, indicating hypoxic like damage and endothelial cell growth and proliferation. Complete depletion of extracellular nucleotides with an apyrase treatment strongly potentiated cell death and progenitor proliferation induced with CoCl2 . Blockade of adenosine P1 and A2A receptors (A2A R) had deleterious effects and deregulated normal timing for progenitor and precursor cell proliferation following photoreceptor damage. ATP via P2RX7 and adenosine via A2A R are survival extracellular signals key for retina regeneration in zebrafish.
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Affiliation(s)
- Matías P Medrano
- Instituto de Fisiología y Biofísica Prof. Bernardo Houssay (IFIBIO-Houssay) UBA y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Antonella Pisera-Fuster
- Instituto de Fisiología y Biofísica Prof. Bernardo Houssay (IFIBIO-Houssay) UBA y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Ramón O Bernabeu
- Instituto de Fisiología y Biofísica Prof. Bernardo Houssay (IFIBIO-Houssay) UBA y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.,Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - María Paula Faillace
- Instituto de Fisiología y Biofísica Prof. Bernardo Houssay (IFIBIO-Houssay) UBA y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.,Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
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19
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Fletcher EL. Contribution of microglia and monocytes to the development and progression of age related macular degeneration. Ophthalmic Physiol Opt 2020; 40:128-139. [PMID: 32017190 DOI: 10.1111/opo.12671] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 12/10/2019] [Accepted: 01/03/2020] [Indexed: 12/12/2022]
Abstract
PURPOSE Age related macular degeneration (AMD) is the leading cause of irreversible vision loss in industrialised nations. Based on genetics, as well as proteome analysis of drusen, the role the innate immune system in the development and/or progression of the disease is well established. Mononuclear phagocytes, such as microglia and monocytes, play critical roles in innate immunity. Here, the role of retinal microglia in mediating normal retinal function, and how these cells change with age is discussed, so as to understand their role in the development and progression of AMD. RECENT FINDINGS It is now known that microglia dynamically survey the neural environment, responding rapidly to even the most subtle neural injury. The dynamic and phagocytic roles of microglia can change with age contributing to alteration in the response of these cells to damage with age. Accumulation of innate immune cells in the subretinal space is a hallmark feature of the development of AMD, reflecting either an increase in migration of monocytes into the retina, or a failure of immune cell elimination from the retina. Furthermore, changes in phagocytic ability of immune cells could contribute to the accumulation of drusen deposits in the posterior eye. SUMMARY An overview of how retinal microglia maintain retinal homeostasis under normal conditions is provided, and then how they contribute to each stage of AMD. In addition, circulating monocytes are altered in those with AMD, contributing to the overall inflammatory state. Understanding the role of cells of the innate immune system in AMD may uncover novel therapeutic targets with which to reduce either the development or progression of disease.
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Affiliation(s)
- Erica L Fletcher
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Victoria, Australia
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20
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Wang AY, Lee PY, Bui BV, Jobling AI, Greferath U, Brandli A, Dixon MA, Findlay Q, Fletcher EL, Vessey KA. Potential mechanisms of retinal ganglion cell type-specific vulnerability in glaucoma. Clin Exp Optom 2019; 103:562-571. [PMID: 31838755 DOI: 10.1111/cxo.13031] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 10/17/2019] [Accepted: 11/16/2019] [Indexed: 12/22/2022] Open
Abstract
Glaucoma is a neurodegenerative disease characterised by progressive damage to the retinal ganglion cells (RGCs), the output neurons of the retina. RGCs are a heterogenous class of retinal neurons which can be classified into multiple types based on morphological, functional and genetic characteristics. This review examines the body of evidence supporting type-specific vulnerability of RGCs in glaucoma and explores potential mechanisms by which this might come about. Studies of donor tissue from glaucoma patients have generally noted greater vulnerability of larger RGC types. Models of glaucoma induced in primates, cats and mice also show selective effects on RGC types - particularly OFF RGCs. Several mechanisms may contribute to type-specific vulnerability, including differences in the expression of calcium-permeable receptors (for example pannexin-1, P2X7, AMPA and transient receptor potential vanilloid receptors), the relative proximity of RGCs and their dendrites to blood supply in the inner plexiform layer, as well as differing metabolic requirements of RGC types. Such differences may make certain RGCs more sensitive to intraocular pressure elevation and its associated biomechanical and vascular stress. A greater understanding of selective RGC vulnerability and its underlying causes will likely reveal a rich area of investigation for potential treatment targets.
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Affiliation(s)
- Anna Ym Wang
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Australia
| | - Pei Ying Lee
- Department of Optometry and Vision Sciences, The University of Melbourne, Melbourne, Australia
| | - Bang V Bui
- Department of Optometry and Vision Sciences, The University of Melbourne, Melbourne, Australia
| | - Andrew I Jobling
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Australia
| | - Ursula Greferath
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Australia
| | - Alice Brandli
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Australia
| | - Michael A Dixon
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Australia
| | - Quan Findlay
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Australia
| | - Erica L Fletcher
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Australia
| | - Kirstan A Vessey
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Australia
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21
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Calbiague VM, Vielma AH, Cadiz B, Paquet‐Durand F, Schmachtenberg O. Physiological assessment of high glucose neurotoxicity in mouse and rat retinal explants. J Comp Neurol 2019; 528:989-1002. [DOI: 10.1002/cne.24805] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 09/09/2019] [Accepted: 10/20/2019] [Indexed: 12/31/2022]
Affiliation(s)
- Víctor M. Calbiague
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Facultad de Ciencias Universidad de Valparaíso Valparaíso Chile
- Programa Doctorado en Ciencias, mención Neurociencias Universidad de Valparaíso Valparaíso Chile
| | - Alex H. Vielma
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Facultad de Ciencias Universidad de Valparaíso Valparaíso Chile
| | - Bárbara Cadiz
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Facultad de Ciencias Universidad de Valparaíso Valparaíso Chile
| | - Francois Paquet‐Durand
- Cell Death Mechanism Group Institute for Ophthalmic Research, University of Tübingen Tübingen Germany
| | - Oliver Schmachtenberg
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Facultad de Ciencias Universidad de Valparaíso Valparaíso Chile
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22
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Pérez de Lara MJ, Avilés-Trigueros M, Guzmán-Aránguez A, Valiente-Soriano FJ, de la Villa P, Vidal-Sanz M, Pintor J. Potential role of P2X7 receptor in neurodegenerative processes in a murine model of glaucoma. Brain Res Bull 2019; 150:61-74. [PMID: 31102752 DOI: 10.1016/j.brainresbull.2019.05.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 04/23/2019] [Accepted: 05/10/2019] [Indexed: 12/20/2022]
Abstract
Glaucoma is a common cause of visual impairment and blindness, characterized by retinal ganglion cell (RGC) death. The mechanisms that trigger the development of glaucoma remain unknown and have gained significant relevance in the study of this neurodegenerative disease. P2X7 purinergic receptors (P2X7R) could be involved in the regulation of the synaptic transmission and neuronal death in the retina through different pathways. The aim of this study was to characterize the molecular signals underlying glaucomatous retinal injury. The time-course of functional, morphological, and molecular changes in the glaucomatous retina of the DBA/2J mice were investigated. The expression and localization of P2X7R was analysed in relation with retinal markers. Caspase-3, JNK, and p38 were evaluated in control and glaucomatous mice by immunohistochemical and western-blot analysis. Furthermore, electroretinogram recordings (ERG) were performed to assess inner retina dysfunction. Glaucomatous mice exhibited changes in P2X7R expression as long as the pathology progressed. There was P2X7R overexpression in RGCs, the primary injured neurons, which correlated with the loss of function through ERG measurements. All analyzed MAPK and caspase-3 proteins were upregulated in the DBA/2J retinas suggesting a pro-apoptotic cell death. The increase in P2X7Rs presence may contribute, together with other factors, to the changes in retinal functionality and the concomitant death of RGCs. These findings provide evidence of possible intracellular pathways responsible for apoptosis regulation during glaucomatous degeneration.
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Affiliation(s)
- María J Pérez de Lara
- Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Complutense University of Madrid, c/Arcos de Jalón 118, E-28037, Madrid, Spain
| | - Marcelino Avilés-Trigueros
- Laboratory of Experimental Ophthalmology, Dept. of Ophthalmology, Faculty of Medicine, University of Murcia and Murcia Institute of Bio-Health Research (IMIB), E-30120, El Palmar, Murcia, Spain
| | - Ana Guzmán-Aránguez
- Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Complutense University of Madrid, c/Arcos de Jalón 118, E-28037, Madrid, Spain
| | - F Javier Valiente-Soriano
- Laboratory of Experimental Ophthalmology, Dept. of Ophthalmology, Faculty of Medicine, University of Murcia and Murcia Institute of Bio-Health Research (IMIB), E-30120, El Palmar, Murcia, Spain
| | - Pedro de la Villa
- Systems Biology Department, Faculty of Medicine, University of Alcalá, Alcalá de Henares, Madrid, Spain
| | - Manuel Vidal-Sanz
- Laboratory of Experimental Ophthalmology, Dept. of Ophthalmology, Faculty of Medicine, University of Murcia and Murcia Institute of Bio-Health Research (IMIB), E-30120, El Palmar, Murcia, Spain.
| | - Jesús Pintor
- Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Complutense University of Madrid, c/Arcos de Jalón 118, E-28037, Madrid, Spain
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23
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Fletcher EL, Wang AY, Jobling AI, Rutar MV, Greferath U, Gu B, Vessey KA. Targeting P2X7 receptors as a means for treating retinal disease. Drug Discov Today 2019; 24:1598-1605. [PMID: 30954685 DOI: 10.1016/j.drudis.2019.03.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 03/07/2019] [Accepted: 03/29/2019] [Indexed: 12/28/2022]
Abstract
Age-related macular degeneration and glaucoma are the commonest causes of irreversible vision loss in industrialized countries. The purine ATP is known to regulate a range of cellular functions in the retina via its action on P2 receptors, especially the P2X7 receptor. Although agents that attenuate P2X7 receptor function have been in development for many years, no compound is currently approved for the treatment of eye disease. However, newer compounds that cross the blood-brain barrier could have potential to reduce vision loss. This review will outline recent information relating to the role of P2X7 in age-related macular degeneration and glaucoma and, subsequently, we will discuss recent developments for attenuating P2X7 receptor function.
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Affiliation(s)
- Erica L Fletcher
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville 3010, Victoria, Australia.
| | - Anna Y Wang
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville 3010, Victoria, Australia
| | - Andrew I Jobling
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville 3010, Victoria, Australia
| | - Matthew V Rutar
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville 3010, Victoria, Australia
| | - Ursula Greferath
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville 3010, Victoria, Australia
| | - Ben Gu
- Florey Institute of Neuroscience and Mental Health, Parkville 3010, Victoria, Australia
| | - Kirstan A Vessey
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville 3010, Victoria, Australia
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Ventura ALM, Dos Santos-Rodrigues A, Mitchell CH, Faillace MP. Purinergic signaling in the retina: From development to disease. Brain Res Bull 2018; 151:92-108. [PMID: 30458250 DOI: 10.1016/j.brainresbull.2018.10.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 09/14/2018] [Accepted: 10/23/2018] [Indexed: 02/07/2023]
Abstract
Retinal injuries and diseases are major causes of human disability involving vision impairment by the progressive and permanent loss of retinal neurons. During development, assembly of this tissue entails a successive and overlapping, signal-regulated engagement of complex events that include proliferation of progenitors, neurogenesis, cell death, neurochemical differentiation and synaptogenesis. During retinal damage, several of these events are re-activated with both protective and detrimental consequences. Purines and pyrimidines, along with their metabolites are emerging as important molecules regulating both retinal development and the tissue's responses to damage. The present review provides an overview of the purinergic signaling in the developing and injured retina. Recent findings on the presence of vesicular and channel-mediated ATP release by retinal and retinal pigment epithelial cells, adenosine synthesis and release, expression of receptors and intracellular signaling pathways activated by purinergic signaling in retinal cells are reported. The pathways by which purinergic receptors modulate retinal cell proliferation, migration and death of retinal cells during development and injury are summarized. The contribution of nucleotides to the self-repair of the injured zebrafish retina is also discussed.
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Affiliation(s)
- Ana Lucia Marques Ventura
- Department of Neurobiology, Neuroscience Program, Fluminense Federal University, Niterói, RJ, Brazil.
| | | | - Claire H Mitchell
- Department of Anatomy and Cell Biology, Ophthalmology, and Physiology, University of Pennsylvania, Philadelphia, PA 19104, United States.
| | - Maria Paula Faillace
- Instituto de Fisiología y Biofísica Prof. Bernardo Houssay (IFIBIO-Houssay), Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina; Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
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Purinergic modulation of frog electroretinographic responses: The role of the ionotropic receptor P2X7. Vis Neurosci 2018; 34:E015. [PMID: 28965497 DOI: 10.1017/s0952523817000128] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The contribution of the purinergic receptors P2X7 (P2X7Rs) to the electroretinographic (ERG) responses was studied by testing the effects of the selective P2X7R antagonist A438079 and the selective P2X7R agonist Bz-ATP on the electroretinograms obtained in perfused frog (Rana ridibunda) eyecup preparations under a variety of stimulation conditions. The P2X7R blockade by 200 µM A438079 diminished the amplitude of the photoreceptor components: the a-wave and the pharmacologically isolated mass receptor potential. In the pure rod-driven and pure cone-driven responses, the amplitude of the postreceptoral ON (b-wave) and OFF (d-wave) components was also diminished. The OFF responses were affected to a greater extent compared to the ON responses. In the mixed rod- and cone-driven responses, obtained in the mesopic intensity range, the b-wave amplitude was increased, while the d-wave amplitude was decreased. The amplitude of the oscillatory potentials was diminished. The relative amplitude changes produced by the P2X7R blockade were greater in the dark-adapted compared to the light-adapted eyes. The application of 100 µM Bz-ATP produced small effects opposite to those of the antagonist, while a prolonged (>20 min) treatment with 1 mM Bz-ATP resulted in a significant amplitude reduction or even abolishment of b- and d-waves. Our results show that endogenous ATP through its P2X7Rs exerts significant, mostly potentiating effects on the ERG photoreceptor and postreceptoral responses. There is a clear ON/OFF asymmetry of the effects on the ERG postreceptoral responses favoring OFF responses: they are always strongly potentiated, while the ON responses are either less potentiated (in the rod-driven and most of the cone-driven responses) or even inhibited (in the mixed rod- and cone-driven responses). The overstimulation of P2X7Rs can produce acute pathological changes, that is, a decrease or abolishment of the ERG responses.
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Chen Z, He L, Li L, Chen L. The P2X7 purinergic receptor: An emerging therapeutic target in cardiovascular diseases. Clin Chim Acta 2018; 479:196-207. [PMID: 29366837 DOI: 10.1016/j.cca.2018.01.032] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 01/19/2018] [Accepted: 01/19/2018] [Indexed: 10/24/2022]
Abstract
The P2X7 purinergic receptor, a calcium permeable cationic channel, is activated by extracellular ATP. Most studies show that P2X7 receptor plays an important role in the nervous system diseases, immune response, osteoporosis and cancer. Mounting evidence indicates that P2X7 receptor is also associated with cardiovascular disease. For example, the P2X7 receptor activated by ATP can attenuate myocardial ischemia-reperfusion injury. By contrast, inhibition of P2X7 receptor decreases arrhythmia after myocardial infarction, prolongs cardiac survival after a long term heart transplant, alleviates the dilated cardiomyopathy and the autoimmune myocarditis process. The P2X7 receptor also mitigates vascular diseases including atherosclerosis, hypertension, thrombosis and diabetic retinopathy. This review focuses on the latest research on the role and therapeutic potential of P2X7 receptor in cardiovascular diseases.
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Affiliation(s)
- Zhe Chen
- Institute of Pharmacy and Pharmacology, University of South China, Hengyang 421001, China
| | - Lu He
- Institute of Pharmacy and Pharmacology, University of South China, Hengyang 421001, China
| | - Lanfang Li
- Institute of Pharmacy and Pharmacology, University of South China, Hengyang 421001, China.
| | - Linxi Chen
- Institute of Pharmacy and Pharmacology, University of South China, Hengyang 421001, China.
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2016 Glenn A. Fry Award Lecture: Mechanisms and Potential Treatments of Early Age-Related Macular Degeneration. Optom Vis Sci 2017; 94:939-945. [DOI: 10.1097/opx.0000000000001124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
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The Role of the P2X7 Receptor in Ocular Stresses: A Potential Therapeutic Target. Vision (Basel) 2017; 1:vision1020014. [PMID: 31740640 PMCID: PMC6835678 DOI: 10.3390/vision1020014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/10/2017] [Accepted: 05/14/2017] [Indexed: 01/30/2023] Open
Abstract
The P2X7 receptor is expressed in both anterior and posterior segments of the eyeball. In the ocular surface, the P2X7 receptor is activated in case of external aggressions: preservatives and surfactants induce the activation of P2X7 receptors, leading to either apoptosis, inflammation, or cell proliferation. In the retina, the key endogenous actors of age-related macular degeneration, diabetic retinopathy, and glaucoma act through P2X7 receptors’ activation and/or upregulation of P2X7 receptors’ expression. Different therapeutic strategies aimed at the P2X7 receptor exist. P2X7 receptor antagonists, such as divalent cations and Brilliant Blue G (BBG) could be used to target either the ocular surface or the retina, as long as polyunsaturated fatty acids may exert their effects through the disruption of plasma membrane lipid rafts or saffron that reduces the response evoked by P2X7 receptor stimulation. Treatments against P2X7 receptor activation are proposed by using either eye drops or food supplements.
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Crooke A, Guzman-Aranguez A, Carracedo G, de Lara MJP, Pintor J. Understanding the Presence and Roles of Ap 4A (Diadenosine Tetraphosphate) in the Eye. J Ocul Pharmacol Ther 2017; 33:426-434. [PMID: 28414592 DOI: 10.1089/jop.2016.0146] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Diadenosine tetraphosphate abbreviated Ap4A is a naturally occurring dinucleotide, which is present in most of the ocular fluids. Due to its intrinsic resistance to enzyme degradation compared to mononucleotides, this molecule can exhibit profound actions on ocular tissues, including the ocular surface, ciliary body, trabecular meshwork, and probably the retina. The actions of Ap4A are mostly carried out by P2Y2 receptors, but the participation of P2X2 and P2Y6 in processes such as the regulation of intraocular pressure (IOP), together with the P2Y2, is pivotal. Beyond the physiological role, this dinucleotide can present on the ocular surface keeping a right production of tear secretion or regulating IOP. It is important to note that exogenous application of Ap4A to cells or animal models can significantly modify pathophysiological conditions and thus is an attractive therapeutic molecule. The ocular location where Ap4A actions have not been fully elucidated is in the retina. Although some analogues show interesting actions on pathological situations such as retinal detachment, little is known about the real effect of this dinucleotide, this being one of the challenges that require pursuing in the near future.
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Affiliation(s)
- Almudena Crooke
- 1 Departamento de Bioquímica y Biología Molecular, Universidad Complutense de Madrid , Madrid, Spain
| | - Ana Guzman-Aranguez
- 1 Departamento de Bioquímica y Biología Molecular, Universidad Complutense de Madrid , Madrid, Spain
| | - Gonzalo Carracedo
- 2 Departamento de Optometría y Visión, F. Óptica, Universidad Complutense de Madrid , Madrid, Spain
| | - Maria J Perez de Lara
- 1 Departamento de Bioquímica y Biología Molecular, Universidad Complutense de Madrid , Madrid, Spain
| | - Jesus Pintor
- 1 Departamento de Bioquímica y Biología Molecular, Universidad Complutense de Madrid , Madrid, Spain
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Ho T, Aplin FP, Jobling AI, Phipps JA, de Iongh RU, Greferath U, Vessey KA, Fletcher EL. Localization and Possible Function of P2X Receptors in Normal and Diseased Retinae. J Ocul Pharmacol Ther 2016; 32:509-517. [DOI: 10.1089/jop.2015.0158] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Tracy Ho
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Australia
| | - Felix P. Aplin
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Australia
| | - Andrew I. Jobling
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Australia
| | - Joanna A. Phipps
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Australia
| | - Robb U. de Iongh
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Australia
| | - Ursula Greferath
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Australia
| | - Kirstan A. Vessey
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Australia
| | - Erica L. Fletcher
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Australia
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Carracedo G, Crooke A, Guzman-Aranguez A, Pérez de Lara MJ, Martin-Gil A, Pintor J. The role of dinucleoside polyphosphates on the ocular surface and other eye structures. Prog Retin Eye Res 2016; 55:182-205. [PMID: 27421962 DOI: 10.1016/j.preteyeres.2016.07.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Revised: 06/30/2016] [Accepted: 07/05/2016] [Indexed: 11/17/2022]
Abstract
Dinucleoside polyphosphates comprises a group of dinucleotides formed by two nucleosides linked by a variable number of phosphates, abbreviated NpnN (where n represents the number of phosphates). These compounds are naturally occurring substances present in tears, aqueous humour and in the retina. As the consequence of their presence, these dinucleotides contribute to many ocular physiological processes. On the ocular surface, dinucleoside polyphosphates can stimulate tear secretion, mucin release from goblet cells and they help epithelial wound healing by accelerating cell migration rate. These dinucleotides can also stimulate the presence of proteins known to protect the ocular surface against microorganisms, such as lysozyme and lactoferrin. One of the latest discoveries is the ability of some dinucleotides to facilitate the paracellular way on the cornea, therefore allowing the delivery of compounds, such as antiglaucomatous ones, more easily within the eye. The compound Ap4A has been described being abnormally elevated in patient's tears suffering of dry eye, Sjogren syndrome, congenital aniridia, or after refractive surgery, suggesting this molecule as biomarker for dry eye condition. At the intraocular level, some diadenosine polyphosphates are abnormally elevated in glaucoma patients, and this can be related to the stimulation of a P2Y2 receptor that increases the chloride efflux and water movement in the ciliary epithelium. In the retina, the dinucleotide dCp4U, has been proven to be useful to help in the recovery of retinal detachments. Altogether, dinucleoside polyphosphates are a group of compounds which present relevant physiological actions but which also can perform promising therapeutic benefits.
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Affiliation(s)
- Gonzalo Carracedo
- Department of Optics II (Optometry and Vision), Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Almudena Crooke
- Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Ana Guzman-Aranguez
- Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Maria J Pérez de Lara
- Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Alba Martin-Gil
- Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Jesús Pintor
- Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain.
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32
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Chavda S, Luthert PJ, Salt TE. P2X 7R modulation of visually evoked synaptic responses in the retina. Purinergic Signal 2016; 12:611-625. [PMID: 27393519 PMCID: PMC5123999 DOI: 10.1007/s11302-016-9522-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 06/24/2016] [Indexed: 10/29/2022] Open
Abstract
P2X7Rs are distributed throughout all layers of the retina, and thus, their localisation on various cell types puts into question their specific site(s) of action. Using a dark-adapted, ex vivo mouse retinal whole mount preparation, the present study aimed to characterise the effect of P2X7R activation on light-evoked, excitatory RGC ON-field excitatory post-synaptic potentials (fEPSPs) and on outer retinal electroretinogram (ERG) responses under comparable conditions. The pharmacologically isolated NMDA receptor-mediated RGC ON-fEPSP was reduced in the presence of BzATP, an effect which was significantly attenuated by A438079 and other selective P2X7R antagonists A804598 or AF27139. In physiological Krebs medium, BzATP induced a significant potentiation of the ERG a-wave, with a concomitant reduction in the b-wave and the power of the oscillatory potentials. Conversely, in the pharmacologically modified Mg2+-free perfusate, BzATP reduced both the a-wave and b-wave. The effects of BzATP on the ERG components were suppressed by A438079. A role for P2X7R function in visual processing in both the inner and outer retina under physiological conditions remains controversial. The ON-fEPSP was significantly reduced in the presence of A804598 but not by A438079 or AF27139. Furthermore, A438079 did not have any effect on the ERG components in physiological Krebs but potentiated and reduced the a-wave and b-wave, respectively, when applied to the pharmacologically modified medium. Therefore, activation of P2X7Rs affects the function in the retinal ON pathway. The presence of a high concentration of extracellular ATP would most likely contribute to the modulation of visual transmission in the retina in the pathophysiological microenvironment.
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Affiliation(s)
- Seetal Chavda
- Visual Neuroscience, UCL Institute of Ophthalmology, London, EC1V 9EL, UK
| | - Philip J Luthert
- Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, EC1V 9EL, UK.,NIHR Biomedical Research Centre in Ophthalmology, London, EC1V 9EL, UK
| | - Thomas E Salt
- Visual Neuroscience, UCL Institute of Ophthalmology, London, EC1V 9EL, UK.
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Aplin FP, Vessey KA, Luu CD, Guymer RH, Shepherd RK, Fletcher EL. Retinal Changes in an ATP-Induced Model of Retinal Degeneration. Front Neuroanat 2016; 10:46. [PMID: 27199678 PMCID: PMC4850166 DOI: 10.3389/fnana.2016.00046] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 04/11/2016] [Indexed: 11/20/2022] Open
Abstract
In rodents and felines, intravitreal administration of adenosine triphosphate (ATP) has been shown to induce photoreceptor death providing a tractable model of retinal degeneration in these species. This study investigated the long term effects of photoreceptor loss in an ATP induced feline model of retinal degeneration. Six normal sighted felines were unilaterally blinded using intravitreal ATP injections and assessed using electroretinography (ERG) and optical coherence tomography (OCT). At 30 h (n = 3) or 12 weeks (n = 3) post-injection, the animals were euthanized and the eyes enucleated. Retinae were sectioned and labeled using immunohistochemistry for markers of cell death, neural remodeling and gliosis. Ongoing cell death and retinal degeneration was observed in the outer retina at both 30 h and 12 weeks following unilateral ATP injection. Markers of mid to late-stage retinal remodeling such as cell displacement and aberrant neurite growth were observed in the inner retina at 12 weeks post-injection. Ganglion cells appeared to remain intact in ATP injected eyes. Müller cell gliosis was observed throughout the inner and outer retina, in some parts completely enveloping and/or displacing the surviving neural tissue. Our data suggests that the ATP injected feline retina continues to undergo progressive retinal degeneration and exhibits abnormalities consistent with a description of retinal remodeling commonly seen in other models of retinal degeneration. These findings validate the use of intravitreal ATP injection in feline as a large animal model of retinal degeneration which may aid in development of therapies aiming to restore visual function after photoreceptor degeneration.
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Affiliation(s)
- Felix P Aplin
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East MelbourneMelbourne, VIC, Australia; Department of Anatomy and Neuroscience, The University of MelbourneMelbourne, VIC, Australia; The Bionics Institute, East MelbourneMelbourne, VIC, Australia
| | - Kirstan A Vessey
- Department of Anatomy and Neuroscience, The University of Melbourne Melbourne, VIC, Australia
| | - Chi D Luu
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East MelbourneMelbourne, VIC, Australia; Department of Surgery (Ophthalmology), The University of MelbourneParkville, VIC, Australia
| | - Robyn H Guymer
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East MelbourneMelbourne, VIC, Australia; Department of Surgery (Ophthalmology), The University of MelbourneParkville, VIC, Australia
| | - Robert K Shepherd
- The Bionics Institute, East MelbourneMelbourne, VIC, Australia; Medical Bionics Department, The University of MelbourneMelbourne, VIC, Australia
| | - Erica L Fletcher
- Department of Anatomy and Neuroscience, The University of Melbourne Melbourne, VIC, Australia
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Giblin JP, Comes N, Strauss O, Gasull X. Ion Channels in the Eye: Involvement in Ocular Pathologies. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2015; 104:157-231. [PMID: 27038375 DOI: 10.1016/bs.apcsb.2015.11.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The eye is the sensory organ of vision. There, the retina transforms photons into electrical signals that are sent to higher brain areas to produce visual sensations. In the light path to the retina, different types of cells and tissues are involved in maintaining the transparency of avascular structures like the cornea or lens, while others, like the retinal pigment epithelium, have a critical role in the maintenance of photoreceptor function by regenerating the visual pigment. Here, we have reviewed the roles of different ion channels expressed in ocular tissues (cornea, conjunctiva and neurons innervating the ocular surface, lens, retina, retinal pigment epithelium, and the inflow and outflow systems of the aqueous humor) that are involved in ocular disease pathophysiologies and those whose deletion or pharmacological modulation leads to specific diseases of the eye. These include pathologies such as retinitis pigmentosa, macular degeneration, achromatopsia, glaucoma, cataracts, dry eye, or keratoconjunctivitis among others. Several disease-associated ion channels are potential targets for pharmacological intervention or other therapeutic approaches, thus highlighting the importance of these channels in ocular physiology and pathophysiology.
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Affiliation(s)
- Jonathan P Giblin
- Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Nuria Comes
- Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | | | - Xavier Gasull
- Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.
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Ho T, Jobling AI, Greferath U, Chuang T, Ramesh A, Fletcher EL, Vessey KA. Vesicular expression and release of ATP from dopaminergic neurons of the mouse retina and midbrain. Front Cell Neurosci 2015; 9:389. [PMID: 26500494 PMCID: PMC4593860 DOI: 10.3389/fncel.2015.00389] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 09/17/2015] [Indexed: 12/20/2022] Open
Abstract
Vesicular nucleotide transporter (VNUT) is required for active accumulation of adenosine tri-phosphate (ATP) into vesicles for purinergic neurotransmission, however, the cell types that express VNUT in the central nervous system remain unknown. This study characterized VNUT expression within the mammalian retina and brain and assessed a possible functional role in purinergic signaling. Two native isoforms of VNUT were detected in mouse retina and brain based on RNA transcript and protein analysis. Using immunohistochemistry, VNUT was found to co-localize with tyrosine hydroxylase (TH) positive, dopaminergic (DA) neurons of the substantia nigra and ventral tegmental area, however, VNUT expression in extranigral non-DA neurons was also observed. In the retina, VNUT labeling was found to co-localize solely with TH-positive DA-cells. In the outer retina, VNUT-positive interplexiform cell processes were in close contact with horizontal cells and cone photoreceptor terminals, which are known to express P2 purinergic-receptors. In order to assess function, dissociated retinal neurons were loaded with fluorescent ATP markers (Quinacrine or Mant-ATP) and the DA marker FFN102, co-labeled with a VNUT antibody and imaged in real time. Fluorescent ATP markers and FFN102 puncta were found to co-localize in VNUT positive neurons and upon stimulation with high potassium, ATP marker fluorescence at the cell membrane was reduced. This response was blocked in the presence of cadmium. These data suggest DA neurons co-release ATP via calcium dependent exocytosis and in the retina this may modulate the visual response by activating purine receptors on closely associated neurons.
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Affiliation(s)
- Tracy Ho
- Visual Neuroscience Laboratory, Department of Anatomy and Neuroscience, The University of Melbourne Parkville, VIC, Australia
| | - Andrew I Jobling
- Visual Neuroscience Laboratory, Department of Anatomy and Neuroscience, The University of Melbourne Parkville, VIC, Australia
| | - Ursula Greferath
- Visual Neuroscience Laboratory, Department of Anatomy and Neuroscience, The University of Melbourne Parkville, VIC, Australia
| | - Trinette Chuang
- Polyclonal Antibody Development, R&D Antibody Development, EMD Millipore Temecula, CA, USA
| | - Archana Ramesh
- Polyclonal Antibody Development, R&D Antibody Development, EMD Millipore Temecula, CA, USA
| | - Erica L Fletcher
- Visual Neuroscience Laboratory, Department of Anatomy and Neuroscience, The University of Melbourne Parkville, VIC, Australia
| | - Kirstan A Vessey
- Visual Neuroscience Laboratory, Department of Anatomy and Neuroscience, The University of Melbourne Parkville, VIC, Australia
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Upregulation of P2RX7 in Cx3cr1-Deficient Mononuclear Phagocytes Leads to Increased Interleukin-1β Secretion and Photoreceptor Neurodegeneration. J Neurosci 2015; 35:6987-96. [PMID: 25948251 DOI: 10.1523/jneurosci.3955-14.2015] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Photoreceptor degeneration in age-related macular degeneration (AMD) is associated with an infiltration and chronic accumulation of mononuclear phagocytes (MPs). We have previously shown that Cx3cr1-deficient mice develop age- and stress- related subretinal accumulation of MPs, which is associated with photoreceptor degeneration. Cx3cr1-deficient MPs have been shown to increase neuronal apoptosis through IL-1β in neuroinflammation of the brain. The reason for increased IL-1β secretion from Cx3cr1-deficient MPs, and whether IL-1β is responsible for increased photoreceptor apoptosis in Cx3cr1-deficient mice, has not been elucidated. Here we show that Cx3cr1-deficient MPs express increased surface P2X7 receptor (P2RX7), which stimulates IL-1β maturation and secretion. P2RX7 and IL-1β inhibition efficiently blunted Cx3cr1-MP-dependent photoreceptor apoptosis in a monocyte/retina coculture system and in light-induced subretinal inflammation of Cx3cr1-deficient mice in vivo. Our results provide an explanation for increased CX3CR1-dependent IL-1β secretion and suggest that IL-1β or P2RX7 inhibition can help inhibit the inflammation-associated photoreceptor cell loss in late AMD, including geographic atrophy, for which no efficient treatment currently exists.
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Reichenbach A, Bringmann A. Purinergic signaling in retinal degeneration and regeneration. Neuropharmacology 2015; 104:194-211. [PMID: 25998275 DOI: 10.1016/j.neuropharm.2015.05.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 05/07/2015] [Accepted: 05/07/2015] [Indexed: 02/01/2023]
Abstract
Purinergic signaling is centrally involved in mediating the degeneration of the injured and diseased retina, the induction of retinal gliosis, and the protection of the retinal tissue from degeneration. Dysregulated calcium signaling triggered by overactivation of P2X7 receptors is a crucial step in the induction of neuronal and microvascular cell death under pathogenic conditions like ischemia-hypoxia, elevated intraocular pressure, and diabetes, respectively. Overactivation of P2X7 plays also a pathogenic role in inherited and age-related photoreceptor cell death and in the age-related dysfunction and degeneration of the retinal pigment epithelium. Gliosis of micro- and macroglial cells, which is induced and/or modulated by purinergic signaling and associated with an impaired homeostatic support to neurons, and the ATP-mediated propagation of retinal gliosis from a focal injury into the surrounding noninjured tissue are involved in inducing secondary cell death in the retina. On the other hand, alterations in the glial metabolism of extracellular nucleotides, resulting in a decreased level of ATP and an increased level of adenosine, may be neuroprotective in the diseased retina. Purinergic signals stimulate the proliferation of retinal glial cells which contributes to glial scarring which has protective effects on retinal degeneration and adverse effects on retinal regeneration. Pharmacological modulation of purinergic receptors, e.g., inhibition of P2X and activation of adenosine receptors, may have clinical importance for the prevention of photoreceptor, neuronal, and microvascular cell death in diabetic retinopathy, retinitis pigmentosa, age-related macular degeneration, and glaucoma, respectively, for the clearance of retinal edema, and the inhibition of dysregulated cell proliferation in proliferative retinopathies. This article is part of a Special Issue entitled 'Purines in Neurodegeneration and Neuroregeneration'.
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Affiliation(s)
- Andreas Reichenbach
- Paul Flechsig Institute of Brain Research, University of Leipzig, Leipzig, Germany.
| | - Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
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BRILLIANT BLUE G DOUBLE STAINING ENHANCES SUCCESSFUL INTERNAL LIMITING MEMBRANE PEELING WITH MINIMAL ADVERSE EFFECT BY LOW CELLULAR PERMEABILITY INTO LIVE CELLS. Retina 2015; 35:310-8. [DOI: 10.1097/iae.0000000000000289] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Sperlágh B, Illes P. P2X7 receptor: an emerging target in central nervous system diseases. Trends Pharmacol Sci 2014; 35:537-47. [PMID: 25223574 DOI: 10.1016/j.tips.2014.08.002] [Citation(s) in RCA: 297] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 08/07/2014] [Accepted: 08/14/2014] [Indexed: 12/19/2022]
Abstract
The ATP-sensitive homomeric P2X7 receptor (P2X7R) has received particular attention as a potential drug target because of its widespread involvement in inflammatory diseases as a key regulatory element of the inflammasome complex. However, it has only recently become evident that P2X7Rs also play a pivotal role in central nervous system (CNS) pathology. There is an explosion of data indicating that genetic deletion and pharmacological blockade of P2X7Rs alter responsiveness in animal models of neurological disorders, such as stroke, neurotrauma, epilepsy, neuropathic pain, multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), Alzheimer's disease, Parkinson's disease, and Huntington's disease. Moreover, recent studies suggest that P2X7Rs regulate the pathophysiology of psychiatric disorders, including mood disorders, implicating P2X7Rs as drug targets in a variety of CNS pathology.
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Affiliation(s)
- Beáta Sperlágh
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1450 Budapest, Hungary.
| | - Peter Illes
- Rudolf Boehm Institute of Pharmacology and Toxicology, University of Leipzig, D-04107 Leipzig, Germany
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Sugiyama T. Role of P2X7 receptors in neuronal death in the retina. Neural Regen Res 2014; 9:579-81. [PMID: 25206858 PMCID: PMC4146243 DOI: 10.4103/1673-5374.130090] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/25/2014] [Indexed: 01/19/2023] Open
Affiliation(s)
- Tetsuya Sugiyama
- Nakano Eye Clinic of Kyoto Medical Co-operative, Kyoto 604-8404, Japan ; Department of Ophthalmology, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan
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Immunolocalization of the P2X4 receptor on neurons and glia in the mammalian retina. Neuroscience 2014; 277:55-71. [DOI: 10.1016/j.neuroscience.2014.06.055] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 06/23/2014] [Accepted: 06/24/2014] [Indexed: 02/07/2023]
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Vessey KA, Greferath U, Aplin FP, Jobling AI, Phipps JA, Ho T, De Iongh RU, Fletcher EL. Adenosine triphosphate-induced photoreceptor death and retinal remodeling in rats. J Comp Neurol 2014; 522:2928-50. [PMID: 24639102 PMCID: PMC4265795 DOI: 10.1002/cne.23558] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 02/06/2014] [Accepted: 02/07/2014] [Indexed: 02/06/2023]
Abstract
Many common causes of blindness involve the death of retinal photoreceptors, followed by progressive inner retinal cell remodeling. For an inducible model of retinal degeneration to be useful, it must recapitulate these changes. Intravitreal administration of adenosine triphosphate (ATP) has recently been found to induce acute photoreceptor death. The aim of this study was to characterize the chronic effects of ATP on retinal integrity. Five-week-old, dark agouti rats were administered 50 mM ATP into the vitreous of one eye and saline into the other. Vision was assessed using the electroretinogram and optokinetic response and retinal morphology investigated via histology. ATP caused significant loss of visual function within 1 day and loss of 50% of the photoreceptors within 1 week. At 3 months, 80% of photoreceptor nuclei were lost, and total photoreceptor loss occurred by 6 months. The degeneration and remodeling were similar to those found in heritable retinal dystrophies and age-related macular degeneration and included inner retinal neuronal loss, migration, and formation of new synapses; Müller cell gliosis, migration, and scarring; blood vessel loss; and retinal pigment epithelium migration. In addition, extreme degeneration and remodeling events, such as neuronal and glial migration outside the neural retina and proliferative changes in glial cells, were observed. These extreme changes were also observed in the 2-year-old P23H rhodopsin transgenic rat model of retinitis pigmentosa. This ATP-induced model of retinal degeneration may provide a valuable tool for developing pharmaceutical therapies or for testing electronic implants aimed at restoring vision.
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Affiliation(s)
- Kirstan A Vessey
- Department of Anatomy and Neuroscience, The University of Melbourne,Melbourne, Victoria, 3010, Australia
| | - Ursula Greferath
- Department of Anatomy and Neuroscience, The University of Melbourne,Melbourne, Victoria, 3010, Australia
| | - Felix P Aplin
- Department of Anatomy and Neuroscience, The University of Melbourne,Melbourne, Victoria, 3010, Australia
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital,East Melbourne, Victoria, 3002, Australia
- The Bionics Institute,East Melbourne, Victoria, 3002, Australia
| | - Andrew I Jobling
- Department of Anatomy and Neuroscience, The University of Melbourne,Melbourne, Victoria, 3010, Australia
| | - Joanna A Phipps
- Department of Anatomy and Neuroscience, The University of Melbourne,Melbourne, Victoria, 3010, Australia
| | - Tracy Ho
- Department of Anatomy and Neuroscience, The University of Melbourne,Melbourne, Victoria, 3010, Australia
| | - Robbert U De Iongh
- Department of Anatomy and Neuroscience, The University of Melbourne,Melbourne, Victoria, 3010, Australia
| | - Erica L Fletcher
- Department of Anatomy and Neuroscience, The University of Melbourne,Melbourne, Victoria, 3010, Australia
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Sanderson J, Dartt DA, Trinkaus-Randall V, Pintor J, Civan MM, Delamere NA, Fletcher EL, Salt TE, Grosche A, Mitchell CH. Purines in the eye: recent evidence for the physiological and pathological role of purines in the RPE, retinal neurons, astrocytes, Müller cells, lens, trabecular meshwork, cornea and lacrimal gland. Exp Eye Res 2014; 127:270-9. [PMID: 25151301 DOI: 10.1016/j.exer.2014.08.009] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 07/24/2014] [Accepted: 08/12/2014] [Indexed: 12/21/2022]
Abstract
This review highlights recent findings that describ how purines modulate the physiological and pathophysiological responses of ocular tissues. For example, in lacrimal glands the cross-talk between P2X7 receptors and both M3 muscarinic receptors and α1D-adrenergic receptors can influence tear secretion. In the cornea, purines lead to post-translational modification of EGFR and structural proteins that participate in wound repair in the epithelium and influence the expression of matrix proteins in the stroma. Purines act at receptors on both the trabecular meshwork and ciliary epithelium to modulate intraocular pressure (IOP); ATP-release pathways of inflow and outflow cells differ, possibly permitting differential modulation of adenosine delivery. Modulators of trabecular meshwork cell ATP release include cell volume, stretch, extracellular Ca(2+) concentration, oxidation state, actin remodeling and possibly endogenous cardiotonic steroids. In the lens, osmotic stress leads to ATP release following TRPV4 activation upstream of hemichannel opening. In the anterior eye, diadenosine polyphosphates such as Ap4A act at P2 receptors to modulate the rate and composition of tear secretion, impact corneal wound healing and lower IOP. The Gq11-coupled P2Y1-receptor contributes to volume control in Müller cells and thus the retina. P2X receptors are expressed in neurons in the inner and outer retina and contribute to visual processing as well as the demise of retinal ganglion cells. In RPE cells, the balance between extracellular ATP and adenosine may modulate lysosomal pH and the rate of lipofuscin formation. In optic nerve head astrocytes, mechanosensitive ATP release via pannexin hemichannels, coupled with stretch-dependent upregulation of pannexins, provides a mechanism for ATP signaling in chronic glaucoma. With so many receptors linked to divergent functions throughout the eye, ensuring the transmitters remain local and stimulation is restricted to the intended target may be a key issue in understanding how physiological signaling becomes pathological in ocular disease.
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Affiliation(s)
| | - Darlene A Dartt
- Schepens Eye Research Institute/Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Vickery Trinkaus-Randall
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USA; Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
| | - Jesus Pintor
- Department of Biochemistry, Faculty of Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Mortimer M Civan
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA; Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Nicholas A Delamere
- Department of Physiology, University of Arizona, Tucson, AZ, USA; Department of Ophthalmology and Vision Science, University of Arizona, Tucson, AZ, USA
| | - Erica L Fletcher
- Department of Anatomy and of Neuroscience, University of Melbourne, Victoria, Australia
| | - Thomas E Salt
- Department of Visual Neuroscience, UCL Institute of Ophthalmology, London, UK
| | - Antje Grosche
- Institute of Human Genetics, Franz-Josef-Strauß-Allee, Regensburg, Germany
| | - Claire H Mitchell
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA; Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, USA.
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Vitanova LA, Kupenova PN. Ionotropic purinergic receptors P2X in frog and turtle retina: glial and neuronal localization. Acta Histochem 2014; 116:694-701. [PMID: 24461518 DOI: 10.1016/j.acthis.2013.12.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 12/12/2013] [Accepted: 12/16/2013] [Indexed: 12/15/2022]
Abstract
Purinergic signaling is represented in both the peripheral and central nervous system (CNS), and in particular in the retina, which may be regarded as a part of the CNS. While purigenic signaling is relatively well studied in mammalian retinas, little is known about it in retinas of lower vertebrates. The aim of present study was to investigate, using immunocytochemistry, the distribution of purinoreceptors P2X in retinas of frog and turtle, which are appropriate models of the brain neuron-to-glia interactions. The results showed widespread expression of all seven ionotropic purinoreceptors (P2X1-P2X7) in both frog and turtle retinas. They were predominantly expressed in Müller cells, the principal glial cells in the retina. All structures typical of Müller cells: the outer and the inner limiting membranes, the cells bodies in the inner nuclear layer, the radial processes in the inner plexiform layer (IPL), and the so called endfeet (frog) or the orthogonal arrays of particles (turtle) in the ganglion cells layer were immunostained. Colocalizations between P2X1-P2X7 and the glial cell marker Vimentin proved that the immunostaining was in the Müller cells. In addition to the glial staining, neuronal staining was also seen as fine puncta in the inner plexiform layer and by small dots and patches in the outer plexiform layer. Some cell bodies of horizontal, amacrine and ganglion cells were also stained. The results obtained imply that the purinergic P2X receptors may significantly contribute to the neuron-to-glia signaling in retinas of the lower vertebrates.
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Sugiyama T. Role of P2X 7 receptors in the development of diabetic retinopathy. World J Diabetes 2014; 5:141-145. [PMID: 24748927 PMCID: PMC3990313 DOI: 10.4239/wjd.v5.i2.141] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 12/04/2013] [Accepted: 01/06/2014] [Indexed: 02/05/2023] Open
Abstract
The P2X7 receptor is one of the members of the family of purinoceptors which are ligand-gated membrane ion channels activated by extracellular adenosine 5’-triphosphate. A unique feature of the P2X7 receptor is that its activation can result in the formation of large plasma membrane pores that allow not only the flux of ions but also of hydrophilic molecules of up to 900 Da. Recent studies indicate that P2X7-mediated signaling can trigger apoptotic cell death after ischemia and during the course of certain neurodegenerative disorders. Expression of the P2X7 receptor has been demonstrated in most types of cells in the retina. This purinoceptor mediates the contraction of pericytes and regulates the spatial and temporal dynamics of the vasomotor response through cell-to-cell electrotonic transmission within the microvascular networks. Of potential clinical significance, investigators have found that diabetes markedly boosts the vulnerability of retinal microvessels to the lethal effect of P2X7 receptor activation. This purinergic vasotoxicity may result in reduced retinal blood flow and disrupted vascular function in the diabetic retina. With recent reports indicating an association between P2X7 receptor activation and inflammatory cytokine expression in the retina, this receptor may also exacerbate the development of diabetic retinopathy by a mechanism involving inflammation.
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46
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Purinergic neuron-glia interactions in sensory systems. Pflugers Arch 2014; 466:1859-72. [DOI: 10.1007/s00424-014-1510-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 03/26/2014] [Accepted: 03/26/2014] [Indexed: 02/06/2023]
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Immunodetection of disease-associated conformers of mutant cu/zn superoxide dismutase 1 selectively expressed in degenerating neurons in amyotrophic lateral sclerosis. J Neuropathol Exp Neurol 2013; 72:646-61. [PMID: 23771221 DOI: 10.1097/nen.0b013e318297fd10] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
We previously showed that some antipurinergic receptor P2X4 antibodies cross react with misfolded forms of amyotrophic lateral sclerosis (ALS)-linked mutant Cu/Zn superoxide dismutase (SOD1). Cross reactivity might be caused by abnormal exposure of an epitope in the inner hydrophobic region of SOD1 that shares structural homology with the P2X4-immunizing peptide. Here, we raised antibodies against the human SOD1 epitope mimicked by the P2X4 immunizing peptide. One of these antibodies, AJ10, is a recognized mutant/misfolded form of ALS-linked mutant SOD1. This was demonstrated in the hybrid motoneuron cell line NSC34 expressing enhanced green fluorescent protein-tagged G943A or A4V mutant SOD1. We also found AJ10 immunoreactivity to be selectively associated with degenerating neurons but not with glial cells in mice overexpressing either SOD1 or SOD1 mutants. Neurons with strongly positive AJ10 immunostaining were often associated with activated microglia displaying neuronophagic activity. AJ10-immunopositive SOD1 aggregates were also found in spinal cord tissue from a patient with a SOD1-linked familial ALS. AJ10-immunoreactive mutant SOD1 conformers were localized in large intracellular protein aggregates with a filamentous amyloid-like organization by ultrastructural immunolabeling and were also detected in neuronal organelles. These data are consistent with the ability of the AJ10 antibody to recognize misfolded conformations of SOD1 shared by different ALS-linked SOD1 mutations but not with the native protein. The neuronal mutant SOD1 conformers detected with AJ10 may promote neuroinflammation and may define a new epitope in SOD1 for ALS research.
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48
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Nitric oxide production and the expression of two nitric oxide synthases in the avian retina. Vis Neurosci 2013; 30:91-103. [PMID: 23721886 DOI: 10.1017/s0952523813000126] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nitric oxide (NO) is known to exert multiple effects on the function of many retinal neurons and their synapses. Therefore, it is equally important to understand the potential sources of NO within the retina. To explore this, we employ a combination of 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate (DAF-FM) based NO detection and immunohistochemistry for the NO synthetic enzymes, neuronal and endothelial nitric oxide synthase (nNOS and eNOS). We find DAF signals in photoreceptors, horizontal cells, amacrine cells, efferent synapses, Müller cells, and cells in the ganglion cell layer (GCL). nNOS immunoreactivity was consistent with the DAF signal with the exception that horizontal cells and Müller cells were not clearly labeled. eNOS-like immunoreactivity (eNOS-LI) was more widespread with photoreceptors, horizontal cells, occasional bipolar cells, amacrine cells, Müller cells, and cells in the GCL all showing labeling. Double labeling with antibodies raised against calretinin, syntaxin, and glutamine synthetase confirmed that horizontal cells, amacrine cells, and Müller cells (respectively) were expressing eNOS-LI. Although little or no nNOS labeling is observed in horizontal cells or Müller cells, the expression of eNOS-LI is consistent with the ability of these cells to produce NO. Together these results suggest that the capability to produce NO is widespread in the chicken retina. We propose that multiple forms of regulation for nNOS and eNOS play a role in the patterning of NO production in the chicken retina.
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Notomi S, Hisatomi T, Murakami Y, Terasaki H, Sonoda S, Asato R, Takeda A, Ikeda Y, Enaida H, Sakamoto T, Ishibashi T. Dynamic increase in extracellular ATP accelerates photoreceptor cell apoptosis via ligation of P2RX7 in subretinal hemorrhage. PLoS One 2013; 8:e53338. [PMID: 23308196 PMCID: PMC3540091 DOI: 10.1371/journal.pone.0053338] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2012] [Accepted: 11/27/2012] [Indexed: 02/05/2023] Open
Abstract
Photoreceptor degeneration is the most critical cause of visual impairment in age-related macular degeneration (AMD). In neovascular form of AMD, severe photoreceptor loss develops with subretinal hemorrhage due to choroidal neovascularization (CNV), growth of abnormal blood vessels from choroidal circulation. However, the detailed mechanisms of this process remain elusive. Here we demonstrate that neovascular AMD with subretinal hemorrhage accompanies a significant increase in extracellular ATP, and that extracellular ATP initiates neurodegenerative processes through specific ligation of Purinergic receptor P2X, ligand-gated ion channel, 7 (P2RX7; P2X7 receptor). Increased extracellular ATP levels were found in the vitreous samples of AMD patients with subretinal hemorrhage compared to control vitreous samples. Extravascular blood induced a massive release of ATP and photoreceptor cell apoptosis in co-culture with primary retinal cells. Photoreceptor cell apoptosis accompanied mitochondrial apoptotic pathways, namely activation of caspase-9 and translocation of apoptosis-inducing factor (AIF) from mitochondria to nuclei, as well as TUNEL-detectable DNA fragmentation. These hallmarks of photoreceptor cell apoptosis were prevented by brilliant blue G (BBG), a selective P2RX7 antagonist, which is an approved adjuvant in ocular surgery. Finally, in a mouse model of subretinal hemorrhage, photoreceptor cells degenerated through BBG-inhibitable apoptosis, suggesting that ligation of P2RX7 by extracellular ATP may accelerate photoreceptor cell apoptosis in AMD with subretinal hemorrhage. Our results indicate a novel mechanism that could involve neuronal cell death not only in AMD but also in hemorrhagic disorders in the CNS and encourage the potential application of BBG as a neuroprotective therapy.
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Affiliation(s)
- Shoji Notomi
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Toshio Hisatomi
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
- Clinical Research Institute, National Hospital Organization Kyushu Medical Center, Fukuoka, Japan
| | - Yusuke Murakami
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Hiroto Terasaki
- Department of Ophthalmology, Graduate School of Medical Sciences, Kagoshima University, Kagoshima, Japan
| | - Shozo Sonoda
- Department of Ophthalmology, Graduate School of Medical Sciences, Kagoshima University, Kagoshima, Japan
| | - Ryo Asato
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
- Clinical Research Institute, National Hospital Organization Kyushu Medical Center, Fukuoka, Japan
| | - Atsunobu Takeda
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yasuhiro Ikeda
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Hiroshi Enaida
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Taiji Sakamoto
- Department of Ophthalmology, Graduate School of Medical Sciences, Kagoshima University, Kagoshima, Japan
| | - Tatsuro Ishibashi
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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Vessey KA, Fletcher EL. Rod and cone pathway signalling is altered in the P2X7 receptor knock out mouse. PLoS One 2012; 7:e29990. [PMID: 22253851 PMCID: PMC3254638 DOI: 10.1371/journal.pone.0029990] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Accepted: 12/11/2011] [Indexed: 01/27/2023] Open
Abstract
The P2X7 receptor (P2X7-R) is expressed in the retina and brain and has been implicated in neurodegenerative diseases. However, whether it is expressed by neurons and plays a role as a neurotransmitter receptor has been the subject of controversy. In this study, we first show that the novel vesicular transporter for ATP, VNUT, is expressed in the retina, verifying the presence of the molecular machinery for ATP to act as neurotransmitter at P2X7-Rs. Secondly we show the presence of P2X7-R mRNA and protein in the retina and cortex and absence of the full length variant 1 of the receptor in the P2X7-R knock out (P2X7-KO) mouse. The role of the P2X7-R in neuronal function of the retina was assessed by comparing the electroretinogram response of P2X7-KO with WT mice. The rod photoreceptor response was found to be similar, while both rod and cone pathway post-photoreceptor responses were significantly larger in P2X7-KO mice. This suggests that activation of P2X7-Rs modulates output of second order retinal neurons. In line with this finding, P2X7-Rs were found in the outer plexiform layer and on inner retinal cell classes, including horizontal, amacrine and ganglion cells. The receptor co-localized with conventional synapses in the IPL and was expressed on amacrine cells post-synaptic to rod bipolar ribbon synapses. In view of the changes in visual function in the P2X7-KO mouse and the immunocytochemical location of the receptor in the normal retina, it is likely the P2X7-R provides excitatory input to photoreceptor terminals or to inhibitory cells that shape both the rod and cone pathway response.
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Affiliation(s)
- Kirstan A. Vessey
- Department of Anatomy and Cell Biology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Erica L. Fletcher
- Department of Anatomy and Cell Biology, The University of Melbourne, Melbourne, Victoria, Australia
- * E-mail:
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